Question

A party mix is made by adding nuts that sell for ​$2.50per kg to a cereal mixture that sells for ​$11 per kg. How much of each should be added to obtain 30 kg of a mix that will sell for ​$2.10per​ kg?

Answer 1

If the mix has x kg of the $2.50 nuts, then the rest (30-x) is $11 nuts. Now just add up the value of each part, and they must add up to the total:

2.50x + 11(30-x) = 2.10*30

now solve for x ...