The figure shows Tap P, Tap Q and an empty tank with a capacity of 81.9 litres. Water flows Tap P at 1.4 litres per minute and from Tap Q at 2.3 litres per minute. Tap P was turned on first. Tap Q was turned on 3 minutes later. The taps were turned off at the same time when the tank was completely filled without overflowing. How much water flowed from Tap P?