The bankerâ€™s discount on Rs. 1600 at 8% per annum is the same as true discount on Rs. 1680 for the same time and at the same rate. The time is :  Pick.
A) 2 months
B) 4.5 months
C) 6.5 months
D) 7.5 months
E) None
Sol.   S.I. on Rs. 1600 = R.D. on Rs. 1680.   âˆ´ Rs. 1600 is the P.W. of Rs. 1680, i.e., Rs. 80 is S.I. on Rs. 1600 at 8%.   âˆ´ Time = [100 * 80 / 1600 * 8] year = 5/8 year = 7.5 months.   Answer 7.5 months
<result>D</result>
The bankerâ€™s discount on Rs. 1600 at 8% per annum is the same as true discount on Rs. 1680 for the same time and at the same rate. The time is :