A village, having a population of 4000, requires 150 litres water per head per day. It has a tank which is 20 m long, 15 m broad and 6 m high. For how many days will the water of this tank last?
Total population of a village = 4000
Water required for 4000 persons for one day = 150×4000=600000 litres
Length of tank (l) = 20 m
Breadth (b) = 15 m
Height (h) = 6 m
∴ Volume of tank = l×b×h
Capacity of water in the tank = 1800×1000
l = 1800000 l (1m3=1000l)
∴ Number of days, the water will last
= 1800000600000= 3 days.