The ratio of the cost price of two articles is 4 : 5. If the first article is sold at 10% profit and the second at 20% profit, find the overall profit percentage.

माना क्रय मूल्य 400 और 500 हैं। कुल क्रय मूल्य = 900। लाभ1 = 40, लाभ2 = 100। कुल लाभ = 140। लाभ% = (140/900)*100 = 15.55%।