Question

A retail store sells two types of walnuts, the Indian walnuts at 120/kilo and chestnuts at $ 60/kilo. How many pounds of each type should Rogelio buy to have a mixture of 20 kilos sold at 80/kilo?

Answer 1

Rogelio should buy: 6.67 kg of indian walnuts and 13.33 kg of chestnuts

The Indian walnuts price: $120 per kg

Chestnuts price: $60 per kg.

We are going to make a system of equations for the two types of walnuts. For the indian walnuts we're going to use the letter "I" and for the chestnuts "C".

Regarding its weight (in kg):

I + C = 20  

I = 20 - C (I)

Regarding the costs ($):

120I + 60C = 80 × 20

120I + 60C = 1600    (II)

Using I in II:

120 × (20 - C) + 60C = 1600

2.400 - 120c + 60c = 1.600

-60C = -800

C = 13.33 KG

So for the indians walnuts we have:

I = 20 - 13.33

I = 6.67 KG