Question

how many kilograms of butter of rs 140 per kg must be mixed with 20 kg of butter worth rs 150 per kg to produce a mixture worth rs 144 per kg

Answer 1

Let x kg of butter @Rs140/kg be added to 20kg of butter @Rs 150/kg
total price = 140×x + 150×20 = 140x + 3000

after mixing, (x+20) kg of butter is produced @Rs144/kg
144×(x+20) = 140x+3000
⇒144x + 144×20 = 140x + 3000
⇒ 144x - 140x = 3000 - 144×20
⇒ 4x = 3000-2880 = 120
⇒ x = 120/4 = 30kg

Answer 2

Answer:

the answer is 30 and 140 /kg