Question

Question 77

In 1975, the consumption of water for human use was about 3850 cu km/yr. It increased to about 6000 cu km/yr in the year 2000. Find the per cent increase in the consumption of water from 1975 to 2000. Also, find the annual per cent increase in consumption (assuming water consumption increases uniformly).

Answer 1

The consumption of water for human in 1975 = 3850 cu km/yr
The consumption of water for human in 2000 = 6000 cu km/yr
Increase in consumption of water in 1975 to 2000 = 6000 - 3850 = 2150 cu km/yr
In percentage $=\frac{2150}{3850}\times 100=55.84\%$
In 25 yr total increase in water consumption = 2150 cu km/yr
$\therefore$ Annualy, i.e. per year water consumption $=\frac{2150}{25}=86cukm/yr$ [$\because$ 2000 - 1975 = 25yr]
$\therefore$ In percentage $=\frac{86}{3850}\times 100=\frac{8600}{3850}=2.23\%$