1. Finding the original quantity
Reverse Percentage or
Finding the original quantity

2. Reverse Percentage
Example:
54% of the adults living on a street own a car. If 162 adults own a car, how many adults live in this street?
162 54
 54 3 1
x 100
300
100

3. Reverse Percentage
Example:
65% of the pages in a magazine are coloured. If there are 52 coloured pages, how many pages altogether? 52 65
 65
0.8 1
x 100 80
100

4. Reverse Percentage
Example:
A bookseller makes 30% on a book and sells it for £9.10. What did she pay originally?
9.10
130
 130
0.07 1
x 100 7
100

5. Reverse Percentage
There are 18 soft-centred chocolates in a box. This is 72% of the total. How many in the box altogether?
12.5% of Fred’s phone calls (9) were not from his friends. How many calls altogether.
A second-hand car is priced at £6440. If it’s value has depreciated by 15%, how much was it worth new?
Some trousers were increased by 20% to £36. What was their original cost.