Mukesh borrowed a sum of Rs. 10000 at simple interest from a bank. After two years he takes Rs. 12000 more as loan and discharge all the debt at the end of next 3 years depositing Rs. 27160 to the bank. What is the rate of interest per annum?
Choose the correct choice from the following options
A) 5% B) 6% C) 8% D) 10% E) None of these
si=27160-(principal amount)=27160-22000= 
<gadget id="calculator">27160-22000</gadget>
<output>5_160</output>
5160.   now,(10000*5*R/100) + (12000*3*R/100)=5160.   500R+360R=5160.....Rate=6%.   ANSWER:6%
<result>B</result>
Mukesh borrowed a sum of Rs. 10000 at simple interest from a bank. After two years he takes Rs. 12000 more as loan and discharge all the debt at the end of next 3 years depositing Rs. 27160 to the bank. What is the rate of interest per annum?