Question

A processing unit is producing a product of 100kg which must contain 15% of fat and this is to be made up from component A with 23% of fat and from component B with 5% of fat. What are the proportions in which these should be mixed?

(a) 44.4 kg of component A to 55.6kg of component B

(b) 67.87kg of component A to 32.13kg of component B

(c) 55.6 kg of component A to 44.4kg of component B

(d) 32.13kg of component A to 67.87kg of component B

This question was addressed to me during a job interview.

The question is from Material and Energy Balances topic in chapter Material & Energy Balances of Food Processing Unit Operations

Answer 1

Right answer is (c) 55.6 kg of component A to 44.4kg of component B

To explain: Let the proportions be X of component A to Y of component B

Then by a mass balance on the fat,

(X × 0.23)+ (Y × 0.05) = (X+Y) × 0.15

A (0.23-0.15) = B (0.15-0.05)

A (0.08) =B (0.10)

A/B= 5/9

Therefore, 100kg of product will have 55.6 kg of component A to 44.4kg of component B.