The population of a town was 8000. In one year, the male population increased by 10% and the female population increased by 8%, while the total population increased by 9%. The number of males in the town was:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 4000
The total increase of 9% is the weighted average of the 10% and 8% increases, so alligation gives the ratio of males to females.
Males (10%) \(\propto 9-8=1\)
Females (8%) \(\propto 10-9=1\)
Males : females \(=1:1\)
Males \(\displaystyle =\frac{8000}{2}=4000\)
The town had 4000 males.