Ratio of male to female population of a town in 2014

Solution

Total male population in 2014 = ({5}/{5+7} x 14400 = {5/12} x 14400 = 6000) Total female population in 2014 = 14400 − 6000 = 8400 When male population is increased by 25% and female population is increased by 25%. New male = 1.25 × 6000 = 7500
New female = 1.25 × 8400 = 10500 Total = 7500 + 10500 = 18000 So, A can be the answer. When male population is increased by 50% and female population is decreased by 10%. New male = 1.50 × 6000 = 9000
New female = 0.90 × 8400 = 7560 Total = 9000 + 7560 = 16560 (≠ 18000) So, B cannot be the answer. When male population is increased by 10% and female population is increased by 20%. New male = 1.10 × 6000 = 6600
New female = 1.20 × 8400 = 10080 Total = 6600 + 10080 = 16680 (≠ 18000) So, C cannot be the answer. Therefore, only A can be the answer. Hence, option a.