Mark’s comic book collection contains
Killer Fish comics and
Shazaam Woman comics. The remainder of his collection consists of Boom comics. If Mark has 70 Boom comic books, how many comic books does he have in his entire collection?
In some problems, even though an amount might be unknown to you, it is actually specified in the problem in another way—specifically, because some other related quantity is given. In these cases, you cannot use Smart Numbers to assign real numbers to the variables. For example, consider this problem:
Mark’s comic book collection contains
Killer Fish comics and
Shazaam Woman comics. The remainder of his collection consists of Boom comics. If Mark has 70 Boom comic books, how many comic books does he have in his entire collection?
Even though you do not know the number of comics in Mark’s collection, you can see that the total is not completely unspecified. You know a piece of the total: 70 Boom comics. You can use this information to find the total. Do not use Smart Numbers here. Instead, solve problems like this one by figuring out how big the known piece is; then, use that knowledge to find the size of the whole. You will need to set up an equation and solve:
Killer Fish
Shazaam Woman
comics that are not Boom
Therefore,
of the books are in fact Boom comic books.
Thus, Mark has 240 comics.
In summary, do pick Smart Numbers when no amounts are given in the problem, but do not pick Smart Numbers when any amount or total is given!
Do not choose Smart Numbers to solve the following problem.
John spends
of his waking hours working,
of his waking hours eating meals,
of his waking hours at the gym, and 2 hours going to and from work. He engages in no other activities while awake. How many hours is John awake?