Most people have two kidneys. The two kidneys filter 180 litres180\text{ litres}180 litres of blood every day.
How much blood does one kidney filter per hour?
3.75 millilitres3.75\text{ millilitres}3.75 millilitres
7.5 litres7.5\text{ litres}7.5 litres
3750 millilitres3750\text{ millilitres}3750 millilitres
7500 millilitres7500\text{ millilitres}7500 millilitres