Let the population of village = N Then, adult's population = 5N/8and adult females = 1/2 x 5N/8 = 5N/16 ∴ illiterate females = 4/5 of adult female population ⇒ 400 = 4/5 x 5N/16 ⇒ N = (400 x 16)/4∴ N = 1600
Given expression = (11.98)² + (0.02)² + 11.98 x x.For the given expression to be a perfect square, we must have11.98 x x = 2 x 11.98 x 0.02 or x = 0.04