14/21*12/21 im stuck on this question on study island and dont know what to put plz !

First you need to simplify each of the fractions as follows:

14/21 = 2/3
12/21=4/7

After that, to multiply them, just multiply the top digits with each other and the bottom digits with each other:

2*4=8 and 3*7=21 so the end result is 8/21.

so (14/21)*(12/21)= 8/21

The amount used= 13.04- 1.9 = 11.14

The answer to this question is either b or c