Ram invested Rs.4500 in SI at (R + 4)% rate of interest per annum for n years and Jegan invested Rs.7500 in CI at R% rate of interest per annum and after 4 years, the total amount obtained by him is Rs.15552. Find the time period of investment of Ram, if Ram obtained an interest of Rs.5400.
a) 12 years
b) 5 years
c) 7 years
d) 10 years
e) None of these
Sol:
7500 * (1 + R/100)4 = 15552
((100 + R)/100)4 = 15552/7500
((100 + R)/100)4 = 1296/625
((100 + R)/100)4 = (6/5)4
(100 + R)/100 = 6/5
500 + 5R = 600
5R = 100
R = 20%
Interest at which Ram invested = 20 + 4 = 24%
4500 * 24 * n/100 = 5400
n = 5 years
