Question

Four fifth of a certain number is 64

Answer 1

Let the number be x

Form equation:

Four fifth of a certain number is 64

⇒ 4/5 x = 64

Solve x:

4/5 x = 64

Divide both sides by 4/5:

x = 64 ÷ 4/5

Change the divide fraction to multiplication fraction:

x = 64 x 5/4

Put into single fraction:

x = 320/4

Simplify:

x = 80

Answer: The number is 80

Answer 2

let the number is x

four fifth of x is 4x/5

According to the given question

4x/5 = 64

4x = 64 x 5

4x = 320

x = 320/4

x = 80

Hence, number is 80.

Check - 80 x 4/5 = 320/5 = 64.

$\bold{Answer: Number \: is \: 80}$