The average age of 125 students in a grop 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?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 18
Average age of a group of students = Total age ÷ No of students
Let the average age of girls =a years
⇒ Average age of boys = a × 120% = 6a/5 years
As per the question;
75 × a + 50 × 6a/5 = 16.2 × 125
⇒ 75a + 60a = 2025
⇒ a = 15
⇒ 6a/5 = 15 × 6/5 = 18