Three-sevenths of a number is 21. What is the number?

1 Answer
Ken C.
Feb 16, 2016

9

Explanation:

There are a few ways to look at this problem. The first is purely mathematical: three-sevenths of 21 is #3/7# multiplied by #21#:
#3/7*21=9#

Another way is visual. Imagine a pizza with 21 slices (sounds very yummy). Now cut this pizza into 7 equal parts. You will find that each part contains exactly 3 slices. Now, eat 3 of these parts. With three slices in each part, you ate 9 slices - which is three sevenths of 21.

enter image source here

Related questions
Impact of this question
12109 views around the world
You can reuse this answer
Creative Commons License