Discussion of Question with ID = 006 under Alligations-and-Mixtures

This is the discussion forum for this question. If you find any mistakes in the solution, or if you have a better solution, then this is the right place to discuss. A healthy discussion helps all of us, so you are requested to be polite and soft, even if you disagree with the views of others. The question and its current solution has also been given on this page.

Question

18 Kg of Grade I sugar costing Rs. 7/Kg is mixed with 9 Kg of Grade II sugar costing Rs. 16/Kg. What is the price of the mixture per Kg?

A

Rs. 10 per Kg.

B

Rs. 11 per Kg.

C

Rs. 9 per Kg.

D

Rs. 13 per Kg.

Soln.
Ans: a

We shall use the alligation formula. If a sample n1 has an average price of A1, and another sample n2 has an average price of A2, then the price of the mixture, A, is determined by the alligation formula as: n1(A - A1) = n2(A2 - A). Putting A2 = 16, A1 = 7, n1 = 18, n2 = 9, we have 18 × (A - 7) = 9 × (16 - A), from where we get A = Rs. 10 per Kg.