Q21
In what proportion should P, Q and S be mixed to make a diet having at least 60% carbohydrate at the lowest per unit cost?
Answer: E
P, Q and S contain 80%, 10% and 45% carbohydrates.
To achieve 60% carbohydrates, proportion of P should be maximum. Hence, options 1 and 3 are eliminated.
Option 2: Carbohydrate content = (320 + 10 + 90)/700 = 420/700 = 60%
Cost per unit = (200 + 200 + 200)/700 = 6/7 = 0.857
Option 4: Carbohydrate content = (240 + 10 + 90)/600 < 60%
Option 5: Carbohydrate content = (320 + 10 + 45)/600 = 62.5%
Cost per unit = (200 + 200 + 100)/600 = 5/6 = 0. 833
P, Q and S in the proportion 4 : 1 : 1 has the lowest cost per unit.
Hence, option (e).