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