The average age of 125 students in a group is 16.2 years. 40%of the students are boys and the rest are girls. The average age of the boys is 20% more than the average age of the girls. What is the average age(in years) of the boys?
Answer & explanation
Correct answer: option 2
Total age of 125 students = 125 × 16.2 = 2025 years
40% = \(\frac{2}{5}\)
Ratio of number of boys to girls = 2 : 3
5R = 125 ⇒ 1R = 25
So , Number of boys = 2 × 25 = 50
Number of girls = 125 - 50 = 75
Ratio of average age of boys to girls = 6 : 5
According to question ,
50 × 6a + 75×5a = 2025
675a = 2025
a = 3
So , Average age of boys = 6 × 3 = 18 years