Question

A residential colony has population of 5400 and 60 litres of water is required per person per day. For the effective utilisation of rain water, a group of people decided for WATER HARVESTING. They constructed a water reservoir measuring 49m×27m×25m to collect the rain water. If this water reserviors is full of water then for how many days it will last for the colony?

Answer 1

Given : A residential colony has a population of 5400 and 60 litres of water is required per person per day.
So,
Total water used per day  =  5400 × 60 =  324000 litre
And
Dimension of water reservoir = 48 ×  27 ×  25 . So  Length  =  48 m  , Breadth  =  27 m and  height  = 25 m

a ) As given during rain the height of water level is 5 m.
So,
Volume of water reservoir ( With height 5 as that is height of water level ) = Total water stored in water reservoir  , The we get

Total water stored in water reservoir  = 48 ×  27 ×  5  =  6345 m3
And
We know
1 m3  =  1000 litre , So

6345 m3 =  6345000 litre

SO, 
That water sufficient for total days  = 6345000324000 = 23512 = 19.58 , So
we can say that water sufficient for nearly 20 days .                                                

Answer 2

i think answer might be 102 or 103 days approx