A village, having a population of 4000, requires 150 litres of water per head per day. It has a tank measuring 20 m × 15 m × 6 m. For how many days will the water of this tank last?

Given :
The tank is cuboidal in shape having its length (l) as 20 m, breadth (b) as 15 m, and height (h) as 6 m.

Capacity of tank
= l x b x h
= (20 x 15 x 6) \({m}^{3}\)
= 1800 \({m}^{3}\) = 1800000 litres

\(\therefore \) Water consumed by the people Of the village in 1 day = (4000 x 150) litres
= 600000 litres

Now, Let water in this tank last for n days.

So, we get that,

Water consumed by all people of village in n days = Capacity of tank
\(\Rightarrow \) = n x 600000 = 1800000
\(\Rightarrow \) n = 3

Therefore, the water of this tank will last for 3 days.