Save guides, add subjects and pick up where you left off with your BBC account. This graph shows the cost of petrol. It shows that 20 litres will cost £23 or £15 will buy 13 litres.

Save guides, add subjects and pick up where you left off with your BBC account. This graph shows the cost of petrol. It shows that 20 litres will cost £23 or £15 will buy 13 litres. Gradient ...