Question

What is the missing numerator?

2/7 = n/21

A. 3
B. 5
C. 6
D. 8

Answer 1

C because 3 x 7 is 21. so you have to do it to the top too.

Answer 2

C. 6

Explanation:

2 n

-------- = -------------

7 21

We can use cross products to solve this.

2 * 21 = 7 * n

42 = 7n

Divide each side by 7

42/7 = 7n/7

6 =n