Question

50 kg of grade a coffee beans is mixed with 100 kg of grade b coffee beans. what will be weight in kg of grade b coffee beans in 60 kg of mixture?

Answer 1

50kg -  coffee A
100kg - coffee B

(coffee A)/ (coffee B) = 50kg/100kg = 1/2

1 + 2 = 3  Entire parts  
1/3 = coffee A
2/3 = coffee B

60kg * 2/3 = (120kg) : 3 = 40kg coffee B