Q5.

Gary's motorbike uses petrol.

Gary needs to mix oil with the petrol.

He mixes oil and petrol in the ratio 1:14 by volume.

Gary is going to ride his motorbike 3000 miles.

Each 20 miles he rides uses 1 litre of the oil and petrol mixture.

A 500 ml bottle of oil costs £3.99

Work out the total cost of the bottles of oil Gary needs to buy.

(1 litre = 1000 m)

You must show all your working.

For every 20 miles he needs 1 liter of oil.

You are told 1 liter = 1000 ml

So for 1 liter of oil he needs to buy 2 bottles (500ml + 500ml = 1000 ml = 1 liter)

The cost of 2 bottles is 3.99 + 3.99 = 7.98

Now divide total miles by miles per liter, which the problem says 20 miles:

3000 miles / 20 = 150

He will need 150 liters of oil.

Multiply the cost for 1 liter by number of liters needed:

150 x 7.98 = £1,197