Question

Jon has 12 stamps with boats on them. This is 40% of his collection. How many stamps are in his entire collection?

Answer 1

30 Stamps

Explanation:

Since 40% of Jon's collection has boat stamps, that means that 20% of his total collection would be 6 stamps (40%/2 and 12/2).

All that's left to do now is get that % to 100, and we can do this by multiplying that and the number of stamps by 5. (20%*5=100, 6*5=30)

This means that Jon has a total of 30 stamps in his collection.

Another way you could do this is simply to multiply 12 by 40%, or 0.4.
This will also give you an answer of 30 stamps.