A dealer wants to mix 20 kg of product A costing rupees 2.40 per kg, with product B, worth rupees 3.30 per kg to produce a mixture worth rupees 2.70 per kg. How man kilograms of product B should he use?
let him use x kg of product B , then
2.4(20) + 3.3x = 2.7(x+20)
48 + 3.3x = 2.7x + 54
.6x = 6
x = 10