Q:

A person lends 40 % of his sum of money at 15 % per annum, 50 % of rest at 10 % per annum and the rest at 18 % per annum rate of interest. What would be the annual rate of interest, if the interest is calculated on the whole sum? 

• 1
  14.4 %
• 2
  13.33 %
• 3
  13.4 %
• 4
  14.33 %