Correct Answer - Option 3 : 67 years
Given∶
20 years ago, the average age of Ramesh and Aadil was 40 years.
The present age of Ramesh, Aadil and John is 60 years.
Formula Used∶
Concept of average, Average = Sum of observations/ Number of Observations
Calculation∶
Let the present age of Ramesh, Aadil and john be a, b and c years respectively.
20 years ago, Ramesh age = (a – 20) years
Aadil age = (b – 20) years
According to question,
[(a – 20) + (b – 20)]/2 = 40
⇒ a + b – 40 = 80
⇒ a + b = 120 ----(1)
Now, Average of present ages of Ramesh, Aadil and John = 60
So, (a + b + c)/3 = 60
⇒ (a + b + c) = 180 ----(2)
Put the value of a + b = 120 from eq (1) in eq. (2), we get
120 + c = 180
⇒ c = 180 – 120 = 60
John’s present age = c = 60 years
After 7 years,
John age = 60 + 7 = 67 years
Hence, the age of John after 7 years is 67 years.
