Craig likes to collect records. last year he had 10 records in his collection. now he has 14 records. what is the percent increase of his collections?

This problem is easy, as 10 is one of the numbers involved. We'll set it up like this:
The percent increase from 10 to 10 is 0%
The percent increase from 10 to 20 is 100%
The percent increase from 10 to 15 is 50%.
Notice a pattern?
Using this pattern, we can tell that the percent increase from 10 to 14 is 40%
Hope this helps! (: