Mixtures Alligation Interests

A man invests Rs. 3,000 at the rate of 5% per annum. How much more should he invest at the rate of 8%, so that he can earn a total of 6% per annum?

  1. Rs. 1,200
  2. Rs. 1,500
  3. Rs. 1,700
  4. Rs. 2,000

Answer

Present rate of interest = 5% (Cheaper quantity)

New rate of interest = 8% (Dearer Quantity)

Mean rate of interest = 6%

Ratio of Dearer Value : Cheaper Value = m-c : d-m = 6-5 : 8-6 = 1 : 2

Dearer Value = Rs.3000/2 = Rs.1500

The correct option is B.