Question

The average age of 4 members of a committee is 60 years while that of 2 senior members is 80 years. If the youngest member is 30 years younger than the remaining member, what is the age remaining member?   
1. 40 years
2. 60 years
3. 55 years
4. 50 years

Answer 1

Correct Answer - Option 3 : 55 years

Given:

The average age of 4 members of a committee is 60 years.

The average age of 2 senior members is 80 years.

The youngest member is 30 years younger than the remaining member.

Concepts used:

Average age = Sum of ages of all members/Total number of members

Calculation:

Sum of ages of all members = 60 × 4 = 240 years

According to the question, the average age of 2 senior members is 80 years.

So, Sum of ages of senior members = 80 × 2 = 160 years

Age of remaining two members of the committee = Sum of ages of all members – Sum of ages of senior members 

⇒ 240 – 160 = 80 years

Let the age of remaining member be x years.

So, Age of youngest member = (x – 30) years 

Age of youngest member + Age of remaining member = 80 years

⇒ x – 30 + x = 80 

⇒ 2x = 110

⇒ x = 110/2

⇒ x = 55 years

∴ Remaining member is 55 years old.