A watch is sold for Rs.440 cash or for Rs.200 cash down payment together with Rs.244 to be paid after one month. Find the rate of interest charged in the installment scheme. Select the correct option
A) 10%  B) 15%  C) 20%  D) 25%  E) None
Explanation:   Principal for the next month = 440 - 200= 
<gadget id="calculator">440 - 200</gadget>
<output>240</output>
240   Amount paid after next month= 244   Therefore interest charged at Rs.240 = 240×1×R/12×100=4   Rate of interest (R) = 20% per annum   Answer 20%
<result>C</result>
A watch is sold for Rs.440 cash or for Rs.200 cash down payment together with Rs.244 to be paid after one month. Find the rate of interest charged in the installment scheme.