There are 56 cookies in a cookie jar, of which 42 are chocolate cookies and 14 are peanut butter cookies. What is the ratio of peanut butter cookies to the total number of cookies in the jar?

Your actual values are 14 peanut butter cookies out of 56 total cookies. Make that a fraction:

14 pb

56 total

Reducing that fraction by dividing numerator and denominator by 14 (the greatest common factor)

, you get

1 peanut butter cookie for a 1:4 ratio

4 total cookies