Help me solve the problems, please! I will give the brainiest!

1/5

1/3

Step-by-step explanation:

For the first problem:

5/7 of ... is 1/7

so

5/7 of x is equal to 1/7

so

(5/7)x = (1/7)

so

x = (1/7)/(5/7)

so

x = 1/5

For the second problem:

5/7 of ... is 5/21

so

5/7 of x is equal to 5/21

so

(5/7)x = (5/21)

so

x = (5/21)/(5/7)

so

x = 1/3

A

Step-by-step explanation:

50 percent is 50/100 and you are trying to find x which is half of 70. A would make the most sense. X should =35