A mobile phone is available for $39000 cash or $17000 as down payment followed by five equal monthly instalments of $4800 each. The simple rate of interest per annum under the instalment plan would be
Pick: A) 18% B) 19% C) 21.2% D) 21.81% E) 22.07%
For this 22,000 a total sum of 5*4800 = 24,000 was pain. (Time is five months, so T = 5/12, as T is in years.)   thus, SI = 2000 or   2000 = (P*R*T)/100   2000 = (22,000*R*5)/(100*12)   R = (2,000*12*100)/22,000*5   R = 21.81%   Therefore answer is 21.81%
<result>D</result>
A mobile phone is available for $39000 cash or $17000 as down payment followed by five equal monthly instalments of $4800 each. The simple rate of interest per annum under the instalment plan would be