Multiple choice

The average age of a group of 10 students is 15 years. When five more students join the group, the average age rises by one year. The average age (in years) of the additional 5 students is

  1. 18

  2. 14

  3. 16

  4. 15

  5. 19
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Initial sum = 10 * 15 = 150. New sum = 15 * 16 = 240. The sum of the 5 additional students is 240 - 150 = 90. Their average is 90 / 5 = 18.

AI explanation

The total age of the initial 10 students is 10 * 15 = 150 years. When five more students join, the total age becomes 15 * 16 = 240 years. The total age of the five new students is 240 - 150 = 90 years. The average age of these five additional students is 90 / 5 = 18 years.

Keep practicing — related questions