Question

Kate paid $27 for a dress that was on sale at 10% off. What was the original price of the dress?

Answer 1

`$30`

Explanation:

If on the sale, a `10%` discount was given, it means that the price of `$27` represents `90%` of the original price.

You can do all percent questions using direct proportion, by matching the numbers with the correct percents.

Let the original price be `x`:

`x/100 = 27/90" "(larr"price in $")/(larr"percent")`

`x = (27 xx 100)/90`

`=$30`

This can also be read as: "Increase `$27` in the ratio `100 : 90`"

`27 xx 100/90 = 30`

The equation which could be formed would be:

`90%` of the full price is `$27`

`90/100x = 27`

`:. x = 27 xx 100/90 =30`