A person buys 5 tables and 9 chairs for ₹15,400. He sells the tables at 10% profit and chairs at 20% profit. If his total profit on selling all the tables and chairs is ₹2,080, what is the cost price of 3 chairs?

₹1,800

According to the question,

10% of 15400 = 1540

20% of 15400 = 3080

Using allegation method

1540                 3080

            2080

1000     :         540

Ratio of cost price of 5 tables and 9 chairs = 1000m : 540m

1000m + 540m = 1540m

1540m = 15400

m = 10

Cost price of 9 chairs = 540 × 10 = 5400

Cost price of 1 chair = 600

∴ Cost price of 3 chairs = 3 × 600 = 1800