Question

Twenty-five decreased by one fifth of a number is 18. Find the number.

Answer 1

35

Explanation:

We have the following equation that represents the problem:

`25 - (1)/(5)x = 18`, where x is the answer we are looking for.

We can subtract both sides by 18:

`25 - 18 - (1)/(5)x = 0`

`7 - (1)/(5)x = 0`

add
`(1)/(5)x` to both sides:

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

multiply both sides by 5:

`35 = x`.

Here, x = 35

Answer 2

35

Explanation:

You have to work backwards, you find what 25-18 is (7)

7 is a fifth of the number you are looking for

so all you have to do is 7 x 5 and you get 35