#### Explanation:

Or:
51div85=Xdiv100%->

#### Explanation:

Here we have an example of reverse percentage. You know the amount AFTER a change has happened, but we do not know the starting amount.

The starting amount represents 100% and the changed amount of $51 represents 85% " from " 100%-15% You can use direct proportion because we are comparing percents and amounts. x/100 = 51/85" "(larr"amount in dollars")/(larr"percent") $85 x = 51 \times 100 \text{ }$by cross-multiplying $x = \frac{51 \times 100}{85}$x =$60

You could also have written the proportion in this form to get the same result:

$\frac{51}{x} = \frac{85}{100}$