Question

21. If the average age of 10 persons is decreased by 2 years when Rahul whose age is 50 years is replaced by Mohan. What is the age of Mohan?​

Answer 1

Answer:

30

Step-by-step explanation:

Age of Rahul is 50

Let age of Mohan be y

Let age of all other 9 people (unchanged) be x

Avg with Rahul - (50+x)/10

Avg with Mohan - (y+x)/10

It's given that if we replace Rahul by Mohan, the avg gets decreased by 2

So, (y+x)/10 = ( (50+x)/10 ) - 2

Solving the equation we will get y = 50 - 20, which is 30.

So, Mohan is 30 yrs old.