Q:

A person invested a sum of Rs. 18,600 at x% per year and another sum that is twice the former at (x+2)% per year, both at simple interest. If the total interest earned on both investments for $$ {3{1\over 2}}$$ years is Rs.23,110.50, then the rate of  interest per year on the second investment is:

• 1
  11 %
• 2
  12.5 %
• 3
  10.5 %
• 4
  13 %