Anglo Chinese School 2007 PSLE Math Prelim Q46

A rectangular container measuring 45 cm by 10 cm by 20 cm is empty at first. Water flows from Tap X at a rate of 1.3 litres per minute and from Tap Y at a rate of 1.2 litres per minute. How long does it take to completely fill up the container if both taps are turned on at the same time? Give your answer in minutes and seconds.

Solution



Volume of tank ----- 45 cm x 10 cm x 20 cm
= 9000 square cm or 9 litres

1 min ----- 1.3 litres/min + 1.2 litres/min = 2.5 litres/min

9 litres divided 2.5 litres/min = 3.6 min or 3 min 36 seconds


Answer: 3 min 36 seconds