  # Finding the Original Quantity After a Percentage Increase or Decrease

In this worksheet, students find the original quantity after a percentage increase/decrease. Key stage:  KS 3

Curriculum topic:   Number

Curriculum subtopic:   Define, Interpret and Compare Percentages

Difficulty level:   #### Worksheet Overview

This activity is about finding the original quantity after a percentage increase/decrease has been applied.

Example 1

In a sale, the price of a DVD player, after a 20% reduction, is £65. Find its price before the sale.

80% of original price = £65.

0.8 × original price = £65.

Original price = £65 ÷ 0.8 = £81.25

Example 2

A sum of money is deposited in a bank account paying 6% interest per annum (every year). After one year there is £1113 in the account. How much money was deposited?

106% of original sum = £1113.

1.06 × original sum = £1113.

Original sum deposited = £1113 ÷ 1.06 = £1050

ALWAYS CHECK that the sale price is less than the original and that an increased quantity is more than the original. 