At the end of the lesson, students should be able to:
In this section we will look at how we can calculate percentage change. To find the percentage change (increase or decrease), we express the change in quantity as a percentage of the original quantity.
Percentage change (increase or decrease) =
Where change = difference between original and new quantity.
The price of a car increased from £1,560 in 2014 to £2,760 in 2015. Find the percentage increase in the cost of the car.
Change (increase in cost of car) = difference between original and new quantity
=£2,760 – £1,560 = £1,200
A car costing £12,050 was reduced to £9,815. What was the percentage change?
Initial cost of car = £12,050.00
New cost of car = £9,815.00
Difference = £12,050 – £9,815.00 = £2,235.00
A computer was sold at $1500 but it now sells at $1000. What is the percentage change in price?
Change (decrease in cost ) = difference between original and new quantity =$1500 – $1000 =$500