What number is to be multiplied with 1/3 to get 1/21

The number to multiply with 1/3 to get 1/21 is 1/7.

Step-by-step explanation:

The question wants us to find the number you can multiply with 1/3 to get 1/21. The number is unknown but when you multiply that unknown number by 1/3 your answer should be 1/21.

Let

the number to be multiplied with = a

Therefore,

1/3 * a = 1/21

a/3 = 1/21

cross multiply

21a = 3

divide both sides by 21

a = 3/21

a = 1/7

The number to multiply with 1/3 to get 1/21 is 1/7.

1/7

Step-by-step explanation:

Since we do not know the number let us use the alphabet A to represent the unknown number

A * 1/3 = 1/21

A/3 = 1/21

Cross multiply both sides

A*21 = 3*1

21A = 3

Divide both sides by the coefficient of A which is 21

21A/21=3/21

A=1/7

Hence the unknown number is 1/7