Question

if 12 subtracted from 9 times a number the answer is five times the number, find the number

Answer 1

Answer :-

The required number is 3.

Solution :-

Let the number be x

9 times a number = 9(x) = 9x

12 subtracted from 9 times a number = 9x - 12

Five times a number = 5(x) = 5x

12 subtracted from 9 times a number = Five times a number

⇒ 9x - 12 = 5x

Transpose - 12 to RHS

⇒ 9x = 5x + 12

Transpose 5x to LHS

⇒ 9x - 5x = 12

⇒ 4x = 12

Transpose 4 to RHS

⇒ x = 12/4

⇒ x = 3

Therefore the required number is 3.

Verification :-

9x - 12 = 5x

Substitute x = 3 in the above equation

⇒ 9(3) - 12 = 5(3)

⇒ 27 - 12 = 15

⇒ 15 = 15