Percentages Toolkit (Cambridge O Level Maths)

A bag contains 54 red marbles and some blue marbles.
36% of the marbles in the bag are red.

Find the number of blue marbles in the bag.

Roberto buys a toy for $5.00.
He then sells it for $4.60.
 
Calculate his percentage loss.
 

............................................. % 

Apples cost Mohsin $0.85 per kilogram to produce. He sells them at a profit of 60%.

Work out the selling price per kilogram of the apples.

$ ...................................................

The price of a book increases from $2.50 to $2.65 .
 
Calculate the percentage increase.
 

............................................... % 

The fares for the train journey are shown in the table below.

For an adult, find the percentage increase in the cost of the standard fare to the premier fare.
 

........................................... %

The number of passengers on a train increases from 63 to 77.
 
Calculate the percentage increase.
 

.................................................% 

Since a school was opened, the number of students has increased by 60%.
There are now 240 students.
 
Calculate the number of students when the school was opened.

In a sale normal prices are reduced by 20%.

A washing machine has a sale price of £464

By how much money is the normal price of the washing machine reduced?

A shop has a sale.

A microwave oven has a sale price of £90
A combination oven has a sale price of £84

Which of these ovens has the greater normal price?
You must show all your working.

Here are three spheres.

The volume of sphere Q is 50% more than the volume of sphere P.
The volume of sphere R is 50% more than the volume of sphere Q.

Find the volume of sphere P as a fraction of the volume of sphere R.

In a sale the original prices are reduced by 15%.

Calculate the sale price of a book that has an original price of $12.
 

$ .................................................

A school has 240 students.
Next year, the number of students will increase by 15%.

Calculate the number of students next year.

At time t = 0 hours a tank is full of water.

Water leaks from the tank.
At the end of every hour there is 2% less water in the tank than at the start of the hour.

The volume of water, in litres, in the tank at time t hours is V_t
Given that
V_o = 2000
V_{t + 1} = kV_t
write down the value of k.

Greg sells car insurance and home insurance.

The table shows the cost of these insurances.

Each month Greg earns

        £530 basic pay
        5% of the cost of all the car insurance he sells
and 10% of the cost of all the home insurance he sells

In May Greg sold

       6 car insurances
and 4 home insurances

Work out the total amount of money Greg earned in May.

Sean wants to go on holiday.
He is going to get a loan of £720 to help pay for the holiday.

Sean will have to pay back the £720 plus interest of 15%.
He will pay this back in 12 equal monthly installments.

How much money will Sean pay back each month?

The table gives information about Ali's spending last month.

Ali's total spending last month was £800

Next month Ali's rent, in pounds, is going to rise by 20%.
His total spending will still be the same.

Express the amount of money Ali will spend on rent next month as a percentage of £800.

Bill buys and sells laptops.

Last month Bill bought 50 laptops.
He paid £400 for each laptop.

He sold

40 of these laptops at a profit of 30% on each laptop
10 of these laptops at a profit of 15% on each laptop

Bill's target last month was to sell all 50 laptops for a total of at least £25 000

Did Bill reach this target?

Renee buys 5 kg of sweets to sell.
She pays £10 for the sweets.

Renee puts all the sweets into bags.
She puts 250 g of sweets into each bag.
She sells each bag of sweets for 65p.

Renee sells all the bags of sweets.

Work out her percentage profit.

The normal price of a television is reduced by 30% in a sale.

The sale price of the television is £350

Work out the normal price of the television.

Jules buys a washing machine.

20% VAT is added to the price of the washing machine.
Jules then has to pay a total of £600

What is the price of the washing machine with no VAT added?