Reverse percentages

Reverse percentages

Multiple Choice

How do we calculate 70 increased by 30%?

• 1.70 x 30

• 0.30 x 70

• 1.30 x 70

• 0.7 x 0.3

Multiple Choice

How do we calculate 43 decreased by 26%?

• 0.26 x 43

• 1.26 x 43

• 0.74 x 43

To increase/decrease by a percentage we

• Add or subtract from a 100%

• Change to a decimal

• Multiply the value by the decimal

Fill in the Blanks

To find the original value after a percentage increase/decrease we need to

by the multiplier.

Multiple Choice

A T-shirt has been reduced by 15% in the sale. It now costs £17, what was the original cost?

• 17 x 0.85

• 17 x 1.15

• $17\div0.85$
  

• $17\div1.15$

Multiple Choice

The amount of chocolates in a tub of celebrations has been increased by 25%. If there are 65 sweets in the tub now, how many were there originally?

• $65\div0.75$

• $65\times0.75$

• $65\times1.25$

• $65\div1.25$

To find the original amount after a percentage has been added/subtracted we

• Find the multiplier

• Divide the new amount by the multiplier.

Poll

How would you rate your understanding of reverse percentages?

(5 being the highest)

• 1

• 2

• 3

• 4

• 5

Open Ended

Is there anything you would like to know further to the information that has been given today?

Multiple Choice

In one year the population of an island increased by 5% to 288960 people. Work out the population of the island before the increase.

• 264,800

• 275,200

• 279,100

• 280,300

Multiple Choice

A holiday is advertised at £760 after it is reduced by 20% in a sale. What was the original price before the sale?

• £800

• £850

• £900

• £950

Multiple Choice

A new car falls in value by 30% in a year. After a year it is worth £8400. Find the price of the car when it was new.

• £15,000

• £12,000

• £10,000

• £9,000

Multiple Choice

A radio sells for £63 after a 40% increase in the cost price. Find the cost price.

• £40

• £45

• £50

• £55

Multiple Choice

I have just paid £88 for my water bill. This is an increase of 10% from last year. How much did I pay last year?

• £80

• £70

• £90

• £78

Multiple Choice

I bought a top for £24. It was in the sale with 20% off. What was the original cost of the top?

• £28

• £30

• £32

• £34