English and Logical Reasoning Prep GuideLogical ReasoningArithmetic Reasoning
The average age of a group of 25 boys is 17 years. If one boy leaves the group, the average age becomes 17.2 years. What is the age of the boy who left the group?
Options
- A12.2 years
- B11.7 years
- C10.8 years
- D14.8 years
Correct answer
A. 12.2 years
Step-by-step solution
Given: The average age of a group of 25 boys is 17 years. If one boy leaves the group, the average age becomes 17.2 years. We need to find the age of the boy who left the group. Solution: Calculate the total age of all 25 boys. Average age of 25 boys (=17 ) years Total age of 25 boys (=25 17=425 ) years Calculate the total age of 24 boys after one leaves. New average age of 24 boys (=17.2 ) years Total age of 24 boys (=24 17.2=412.8 ) years Find the age of the boy who left the group. Age of the boy who left (= ) To