A gym charges $35 per month for full access to their workout equipment. Mrs. Lewis has a $140 gift certificate to the gym. For how many months can Mrs. Lewis work out using the gift certificate?

Question

1430 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-12-27T02:05:39

4

Let's work this through month by month, and then again in a more "math-y" way.

Mrs. Lewis has the $140 gift certificate (and let's add that it's a Christmas present and she'll start working out January of the new year).

So for the 1st month, January, she spends $35 of the gift certificate:

#140-35=105#

And the second month, February, she spends another $35 of the gift certificate:

#105-35=70#

March, the third month:

#70-35=35#

And finally in April, the 4th month:

#35-35=0#

The gift certificate runs out. The answer is therefore 4 months.

How can we do this in a quicker and more math-y fashion? We can divide the amount of the gift certificate by the amount the gym charges each month:

#140/35=4#

And maybe it'll be easier to see if I add units to that math:

#(140 $)/(35 $/"mo")=(cancel140^4/1 cancel$/1)(1/cancel35 "mo"/cancel$)=4 "mo"#