Question

If you know that 84 is 70% of a whole, explain how you can use proportional reasoning to determine the whole

Answer 1

Set up an equation.

Let w = whole number

84 = 0.70w

84/0.70 = w

120 = w

Answer 2

The whole number was 120.

Explanation:

Let the whole number that is to be determined is = x

Then 70% of this number = 70% of x

Replace 'of' by the sign of multiplication

70% of x =
`x* (70)/(100)`

= 0.7x

If 70% of x is equal to 84 then the expression will be

0.7x = 84

x =
`(84)/(0.7)`

x =
`(840)/(7)`

x = 120

Therefore, the whole number was 120.