Question

If 30% of a number is 42 and 70% of the same number is 98, find 40% of that number.

Answer 1

56 is 40% of the original number

Explanation:

Let
`n` represent the original number

We are given that

30% of number is 42

70% of the same number is 98

Lets convert the precents to decimals

30% as a decimal is
`0.3`

70% as a decimal is
`0.7`

We can create an equation for each scenario

`0.3n=42\\0.7n=98`

We can choose either one to evaluate
`n`.

`0.3n=42`

Lets solve for
`n`.

Divide both sides by
`0.3`.

`n=(42)/(0.3)`

Evaluate
`(42)/(0.3)`.

`n=140`

Now that we know what the original number is we can calculate what 40% of the number is.

40% as a decimal is
`0.4`.

`140*0.4=56`