A sum fetched a total simple interest of Rs. 144 at the rate of 15 p.c.p.a. in 1 year 6 months. What is the sum?  Select.
A) 490 B) 850 C) 580 D) 640 E) 760
Sol.   Principal = Rs. [100 * 144 / 15 * (18/12)] = Rs. [14400 / 22.5] = Rs. 640.   Answer 640
<result>D</result>
A sum fetched a total simple interest of Rs. 144 at the rate of 15 p.c.p.a. in 1 year 6 months. What is the sum?