The average expenditure of a man for the first five months was ₹120, and for the next seven months it was ₹130. What was his monthly average income if he saved ₹290 that year?

Explanation

First 5 months' expenditure = 5 × ₹120 = ₹600. Next 7 months' expenditure = 7 × ₹130 = ₹910. Total expenditure = ₹1,510. Adding savings of ₹290 gives an annual income of ₹1,800.

₹1,800/12 = ₹150

Therefore, the monthly average income was ₹150.