The average age of Mona, Neha, Oishi, and Roza is 22 years. The average age of Mona, Neha, and Oishi is 20 years and the average age of Neha, Oishi, and Roza is 24 years. Find the average age of Neha and Oishi.

Question: The average age of Mona, Neha, Oishi, and Roza is 22 years. The average age of Mona, Neha, and Oishi is 20 years and the average age of Neha, Oishi, and Roza is 24 years. Find the average age of Neha and Oishi.

Solution:
Given,
Mona + Neha + Oishi + Roza = (22 × 4) = 88 years.......(1)
Mona + Neha + Oishi = 20 × 3 = 60 years.............(2)
Neha + Oishi + Roza = 24 × 3 = 72 years...............(3)

now from (1) - (2)
Roza’s age = (88 - 60) = 28 years

from (3) ⇒ Neha + Oishi = (72 - 28) = 44 years
∴ the average age of Neha and Oishi = 44/2 = 22 years