If the sum of the consecutive integers from x to (x + 6), inclusive, is 56, what is x?

301

 

Answer: 5

There are 7 integers in the sum, so the average integer is images In a consecutive set, the average is also the middle term. Thus, the 4th integer in this list is 8: {5, 6, 7, 8, 9, 10, 11}. x is 5.

Alternatively,

images

 

What is the average of 11.5, 12.25, 13, 13.75, 14.5, 15.25, and 16?

302

 

Answer: 13.75

Give the calculator a rest! The terms in this set are equally spaced 0.75 apart. In an evenly spaced set, the average of the set equals the middle term (if an odd number of terms) or the average of the two middle terms (if an even number of terms). This set has 7 terms, so the middle term is the 4th, which is 13.75.

 

Quantity A Quantity B
   
The average of –2x, –x, 0, x, 2x, and 3x. 0

303

 

Answer: (D) The relationship cannot be determined from the information given.

In Quantity A, the 6 terms are evenly spaced x apart. The average of the set is the average of the two middle terms (since there are an even number of terms), which is images Be careful! It is tempting to think this list is ordered from low to high, negative to positive, but that is only true if x is positive. If x is negative, the list is ordered high to low, positive to negative. Either way, the average is images, but this could be greater or less than 0. In fact, x could even be 0, making all the terms and the average in Quantity A equal 0.

 

Raffle tickets with consecutive integers 1,014 to 2,345, inclusive, were sold. Each ticket has exactly one unique integer on it. How many tickets were sold?

304

 

Answer: 1,332

Subtract the low number from the high number and “add one before you are done.”

      images

 

A, B, and C lie on a number line such that B is the midpoint between A and C.

Quantity A Quantity B
   
A B

305

 

Answer: (D) The relationship cannot be determined from the information given.

The number line could look like this:

        images

Or like this:

        images

Either A or B could be the greater number.

 

images

Quantity A Quantity B
   
A × B C × D

306

 

Answer: (D) The relationship cannot be determined from the information given.

From the number line, it is clear that A and B are both negative and C and D are both positive. Thus, both quantities are positive, but no scale is provided, so nothing is known about the relative values.

One possibility is that A = –3, B = –2, C = 4, D = 5. Since (–3)(–2) = +6 and (4)(5) = +20, Quantity B is bigger.

Another possibility is that A = –9, B = –7, C = 7, D = 8. Since (–9)(–7) = +63 and (7)(8) = +56, Quantity A is bigger.

 

images

On the number line above, B is twice as far from C as from A, and D is twice as far from B as from C. What is the ratio of length images to length images?

307

 

Answer: images

B is twice as far from C as from A”: Label the distance between B and A as x. The distance between B and C is twice that, or 2x.

D is twice as far from B as from C”: If the distance between C and D is 2x, then D is 2x + 2x = 4x from B, which is “twice as far…as from C.”

images

images

 

images

Quantity A Quantity B
   
|P| Q

308

 

Answer: (B) Quantity B is greater.

P is between –5 and 0, so |P| is between 0 and 5.

Q is between 5 and 10.

Thus, Q > 5 > |P|.

 

images

If the tick marks on the number line above are evenly spaced, what is the value of x?

309

 

Answer: images

images is three tick marks to the right of images In other words, 3 intervals equals

images Each interval is images, then.

x is three tick marks to the right of images, so x is images greater than images

images

 

images

Based on the number line above, which of the following must be true? Select all that apply.

 

[A] xy < 0

[B] zy < xy

[C] zx > xy

[D] zy > zx

310

 

Answer: [A], [B] and [D]

Note that only one number, 0, is labeled on the number line. From their relative positions, x and z are positive while y is negative. It is also true that z > x. Beyond that, however, the values are not known, and don't assume the figure is drawn to scale.

[A] TRUE: x is positive and y is negative, so xy < 0

[B] TRUE: zy < xy divided by y becomes z > x (flip the inequality sign because y is negative). It is true that z > x.

[C] UNCERTAIN: Both (zx) and (xy) are positive, but without known values, either could be greater.

[D] TRUE: Subtract z from both sides to get – y > – x. Divide by –1 (don't forget to flip the inequality sign!) to get y < x. This must be true because y is negative and x is positive. Alternatively, (zy) is the distance between y and z on the line, which is clearly greater than the distance between x and z, (zx).

 

Simplify: images

311

 

Answer: images

images

 

Simplify: images

312

 

Answer: images

images

 

Simplify: images

313

 

Answer: 75

images

 

What is the length of the diagonal of a square with side length images?

314

 

Answer: 16

The diagonal of a square is always images times the side length. For this square, the diagonal is images

 

The diagonal of a square is 10. What is the area of the square?

315

 

Answer: 50

The diagonal of a square is always images times the side length. Conversely, the side length is always the diagonal divided by images For this square, the side length is images

Area of a square is the side length squared: area images

 

The area of a rectangle is 60 and the diagonal length is 13. What is the perimeter of the rectangle?

316

 

Answer: 34

When the diagonal of a rectangle is 13, you should at least test the possibility that the diagonal creates two 5–12–13 right triangles. If so, the rectangle area would be (5)(12) = 60, which is exactly what this question specifies. Thus, perimeter = 2(L + w) = 2(12 + 5) = 34.

 

If two sides of a triangle are each 8 inches and the third side is x inches, what are possible values for x?

317

 

Answer: 0 < x < 16

The sum of any two side lengths of a triangle will always be greater than the third side. The sum of 8 and 8 is 16, which must be greater than third side x. The sum of x and either side 8 must be greater than the other side 8: x + 8 > 8, or x > 0.

 

Quantity A Quantity B
   
The area of a triangle with side lengths images, 3, and images 3

318

 

Answer: (B) Quantity B is greater.

The triangle side lengths in Quantity A are special: images, 3, and images can be written as images, and images In other words, the side lengths are in the ratio images, which you should recognize as the ratio of the side lengths in a 30–60–90 triangle. Multiplying by images doesn't change any angles;s it just increases the size of the triangle. Thus, the base and height of this right triangle are images and 3, so the area images

 

images

What is the area of the triangle above?

319

 

Answer: images

The height and hypotenuse of the right triangle are known. Use Pythagorean Theorem to determine the base.

images

The area of the triangle is images

 

images

Quantity A Quantity B
   
a b

320

 

Answer: (B) Quantity B is greater.

The longest side of a triangle is opposite the largest angle, and the smallest side is opposite the smallest angle.

6 is the shortest side of the triangle, so a° is the smallest angle of this triangle. 9 is the longest side of the triangle, so b° is the largest angle of this triangle. Thus, b > a.

 

images

In the figure above, what is x?

321

 

Answer: 40

The sum of the angles in a triangle is 180:

180 = x + 87 + 53

180 = x + 140

  40 = x

 

In a triangle with angles 45°, 45°, and 90°, a side length measures images What could the other side lengths be?

322

 

Answer: 5, images, and/or 10

In a 45–45–90 triangle, the ratio of the side lengths is x : x : images

The known side could be the hypotenuse, in which case the sides are 5 : 5 : images Or, the known side could be one of the perpendicular legs, in which case the hypotenuse is images, and the side ratio is images

 

images

Quantity A Quantity B
   
images 2

323

 

Answer: (C) The two quantities are equal.

This is a right triangle, so by Pythagorean Theorem, the hypotenuse is images The sides of this triangle are in the ratio 1 :images: 2, which you should recognize as a property of a 30–60–90 triangle. The shortest side, 1, is across from the smallest angle: y = 30. The middle side, images, is across from the middle angle: x = 60.

Therefore, images

 

x = 1,234,567.89

Quantity A Quantity B
   
The digit in the hundredths place of x The digit in the hundredths place of x

324

 

Answer: (A) Quantity A is greater.

Quantity A: The hundredths place of 1,234,567.89 is 9.

Quantity B: The ten thousands place of 1,234,567.89 is 3.

9 > 3

 

Which of the following equals 48,290?

 

Select all that are equal.

 

[A] 482.9 × 102

[B] 48.29 × 10–3

[C] 0.4829 × 104

[D] 482,900 × 10–1

[E] 0.04829 × 106

325

 

Answer: [A], [D], and [E]

What is equal to 48,290?

[A] EQUAL. 482.9 × 102 = 48, 290

[B] NOT. 48.29 × 10–3 = 0.04829

[C] NOT. 0.4829 × 104 = 4,829

[D] EQUAL. 482,900 × 10–1 = 48, 290

[E] EQUAL. 0.04829 × 106 = 48, 290

 

What is images, rounded to the nearest integer?

326

 

Answer: 9

images

or

images

 

0.00021 is what percent of 0.007?

327

 

Answer: 3%

Normally, for an “X is what percent of Y?” question, you would do images in your calculator. While you could just plug these numbers into the calculator and divide, the risk of misplacing the decimal is high, so a secondary “human calculator” check is a good idea.

Shift the decimal in both top and bottom by 5 places before dividing, eliminating decimals altogether.

images

 

What is 0.000002 × 50,000?

328

 

Answer: 0.1

While you could just plug into the calculator and multiply, the risk of misplacing the decimal means that a secondary “human calculator” check is a good idea.

“Trade” decimal places. Move the decimal 5 to the right in the first number and 5 to the left in the second number, getting:

0.2 × 0.5

Half of 0.2 is 0.1.

 

Quantity A Quantity B
   
The ten thousandths digit of images The hundred thousandths digit of images

329

 

Answer: (A) Quantity A is greater.

images is a “terminating” decimal, as there are only prime factors of 2 and 5 in the denominator: 20 = (2)(2)(5). Where does it terminate? images = 0.55, so every digit past the hundredths place equals 0. Thus, Quantity B is 0.

images is a repeating decimal, as there are prime factors other than 2 or 5 in the denominator: 99 = (3)(3)(11). Determine the repeating pattern: images The hundred thousandths digit is the 5th digit after the decimal, so Quantity A is 3. (Either digit after the decimal would have been greater than 0, actually.)

 

Change the improper fraction images to a mixed number.

330

 

Answer: images

images is images short of images Thus, images as a mixed number is images

Alternatively, divide 3 into 89. It goes in evenly 29 times. (29)(3) = 87, so 89 – 87 = 2 thirds are left over.

 

Simplify: images

331

 

Answer: images

images

 

Simplify: images

332

 

Answer: images or images

images

 

Quantity A Quantity B
   
images images

333

 

Answer: (B) Quantity B is greater.

Both quantities are close to a benchmark value of images

Quantity A: images is slightly less than images, as the numerator is smaller.

Quantity B:images is slightly greater than images, as the denominator is smaller.

Quantity B > images > Quantity A.

 

Simplify: images

334

 

Answer: images

Don't split the denominator! You must add the numbers in the denominator before dividing. Parentheses can serve as a visual reminder, as Parentheses come first in the PEMDAS order of operations.

images

 

Given x ≠ 2, simplify: images

335

 

Answer: images

images

 

images of the fish in a certain tank are clownfish. images of the other fish were first placed in the tank yesterday. Placing those fish in the tank increased the total number of fish in the tank by what fraction?

336

 

Answer: images

(8)(5) = 40, which is a Smart Number for the total number of fish in the tank, as it is divisible by every denominator in the constraints. If there are 40 fish in the tank, images of the fish are clownfish. There are 40 – 15 = 25 fish of other types. If images of these 25 others were placed in the tank yesterday, images fish were placed in the tank yesterday. There are 40 fish now, so before the 10 were added there were 40 – 10 = 30. The number of fish increased by images of the original number of fish.

 

If x is even and y is odd, what is 4x + yx + y2?

 

(A) Definitely odd

(B) Definitely even

(C) Could be either odd or even

337

 

Answer: (A) Definitely odd

images

 

If all variables are integers, and the product abcd is odd, what is abc + bcd + acd?

 

(A) Definitely odd

(B) Definitely even

(C) Could be either odd or even

338

 

Answer: (A) Definitely odd

Since the product abcd is odd, none of the variables can be even. A single even integer would introduce a factor of 2 that would make the resulting product even. So, each variable is odd.

images

 

If m, n, and p are consecutive integers such that m < n < p, what is m2 + n2 + np?

 

(A) Definitely odd

(B) Definitely even

(C) Could be either odd or even

339

 

Answer: (A) Definitely odd

Since consecutive integers alternate O, E, O, E…etc., there are two cases:

images

Both wind up odd.

 

x is a prime number and y is a positive multiple of x. What is xy?

 

(A) Definitely odd

(B) Definitely even

(C) Could be either odd or even

340

 

Answer: (C) Could be either odd or even

If x is a prime number, it could be even (2 only) or odd (all the other prime possibilities). If y is a positive multiple of x, it could be either an even number or an odd number times x. Thus, there are several cases:

images

 

If j and k are integers such that j2 is even and k3 is odd, what is 2k + 5jk + 3j?

 

(A) Definitely odd

(B) Definitely even

(C) Could be either odd or even

341

 

Answer: (B) Definitely even

Since j is an integer and j2 is even, j itself must be even.

Since k is an integer and k3 is odd, k itself must be odd.

images

 

If f is an integer, what is f2 + 15f + 50?

 

(A) Definitely odd

(B) Definitely even

(C) Could be either odd or even

342

 

Answer: (B) Definitely even

If f is even, then f2 + 15f + 50 = E2 + 15E + 50 = E + E + E = E

If f is odd, then f2 + 15f + 50 = Odd2 + 15(Odd) + 50 = O + O + E = E

Either outcome is even.

Alternatively, factor:

f2 + 15f + 50 = (f + 5)(f + 10) = (f + Odd)(f + Even)

Since one term adds Odd and the other adds Even, there will always be one even and one odd term in the product. Both (E)(O) and (O)(E) are even.

 

If x and y are integers, xy = z and x + y = 11, what is z2 – 2z?

 

(A) Definitely odd

(B) Definitely even

(C) Could be either odd or even

343

 

Answer: (B) Definitely even

Since x + y = 11 = odd, x and y must be odd and even, respectively, or vice versa. x and y cannot both be odd or both be even, as x + y would be even in those cases.

The product xy will always be even, as both (E)(O) and (O)(E) are even. Thus, z is even.

z2 – 2z = E2 – 2E = EE = E

 

Is zero odd, even, or neither? Why?

344

 

Answer: Zero is even.

Why?

(1) An even number is a number that, when divided by 2, yields an integer result. Note that images an integer.

(2) On the number line, odd and even integers alternate. That is, every even integer is between two odd integers. Every odd integer is between two even integers. Keeping this pattern, the even integer zero is between the odd integers –1 and +1. The odd integer 1 is between the even integers 0 and 2.

 

If x and y are positive integers and 3xy2 = 1,200, what is xy?

images

345

 

Answer: 20

From the factor tree for 1,200 and the given constraint, 3xy2 = 312452.

y cannot have a factor of 3, as y2 would then have two factors of 3, but there is only one factor of 3 in 1,200. Thus, 3x = 31, and x = 1. Consider the remaining terms and factors:

y2 = 2452

y2 = (22)252

y2 = (22 × 5)2

y = 22 × 5 = 20

So x = 1, y = 20, and xy = 20.

 

Round the following numbers to the nearest 0.01.

 

(A) 1.378

(B) 0.2547

(C) 9.355

346

 

Answer: (A) 1.38 (B) 0.25 (C) 9.36

When rounding to the nearest 0.01 (hundredth),

 

•  Round UP when the thousandths digit is 5, 6, 7, 8, or 9.

•  KEEP the hundredths digit as-is when the thousandths digit is 0, 1, 2, 3, or 4. (This is just like truncating every digit after the 0.01 place.)

(A) The thousandths digit is 8, so round the 7 in the hundredths place UP to 8. Result: 1.38

(B) The thousandths digit is 4, so truncate every digit after the hundredths place. Result: 0.25

(C) The thousandths digit is 5, so round the 5 in the hundredths place UP to 6. Result: 9.36

 

What is 0.472 as a fully reduced fraction?

347

 

Answer: images

Use the place value of the last digit in the decimal as the denominator: Here, 0.472 ends with the thousandths place, so put 1000 in the denominator. Put the decimal's digits in the numerator. Then simplify. 472 is divisible by 8, as is 1,000.

images

 

Simplify: images

348

 

Answer: 1

images

 

Simplify, and express the answer as a mixed fraction.

images

349

 

Answer: images

It is simplest to sum the whole number and the fractional parts of these terms separately:

images

 

Solve for x.

images

350

 

Answer: x = –2 or 8

images, so either (3 – x) = 5 or (3 – x) = –5. Solve both.

images