DRDO Multi tasking staff Model paper 8

Let the average age of 15 men be X.
⇒ Sum of ages of 15 men = 15X
Average is increased by 5 years when two of them whose ages are 44 and 35 years are replaced by another 2 persons
Let the sum of the ages of the 2 new persons be Y.
⇒ New average = X + 5
New sum of the ages of 15 men = 15(X + 5) = 15X + 75
⇒ 15X – 44 – 35 + Y = 15X + 75
⇒ Y = 154
Average age of the two new persons = 154/2 = 77 years