Question

Niki uses 15 litres of water every minute when she has a shower.

Answer 1

15 litres per minute times three minutes is 45 litres for three minutes, and half a minute's worth of water in the shower is 7 1/2 (half of 15). 45+7 1/2= 52 1/2 litres of water.The difference between 100 and 52 1/2 is 47 1/2, which is our final answer.