An investment of d dollars at k percent simple annual interest yields &600 interest over a 2-year period. In terms of d, what dollar amount invested at the same rate will yield $2,400 interest over a 3-year period?
答案是8d/3, 我心情激动算出4d/3.
怎么回事？！？！？
求助哪位高手指教！！！多谢！！！作者: cckjenius 时间: 2011-3-31 19:59
SI = P*N*R /100
where p-principal n- number of years r-rate
SI- SIMPLE INTEREST
GIVEN:
600 = d * 2 * k/100
kd = 600*50 (1)
Lets say x is the principal we need to find in terms of d
2400 = x * 3 *k/100
x = 2400 *100/3k
= 2400 * 100 * d / 3 * 600 *50 (from (1) k = 600*50/d)
