**Problem 1:** An equal principal was invested in two banks first offering 15% simple interest and the second offering compound interest of 20% if the difference of interest from both banks after 3 years was Rs.417. Find the principal invested in each bank?

Solution:

Simple Interest=15*3=45%

Compound Interest=20+20+=44%

44+20+=72.8%

72.8-45=27.8%

27.8%——–>417

100%———->?

**Problem 2:** Simple interest on a principal of 2 years is 108.80 and compound interest on same principal for the same time period and rate of interest is RS 115.60. Find the rate of interest?

Solution: Simple interest on a principal of 2 years is 108.80

Note: Simple interest is same for every year

54.40 S.I for the first year

54.40 S.I for the second year

Compound interest on same principal for the same time period and rate of interest is Rs.115.60

115.60-108.80=6.8

1st year C.I is 54.40

2nd year C.I is 54.40+6.8

54.40| 54.40| 6.8

54.40

%

**Problem 3:** A sum of Rs.2592 was invested in two banks the first bank offers C.I of % compounded annually whereas the second bank offers S.I of %. Find the difference between S.I and C.I of 2 years 6 months?

Solution:

C.I is %=

S.I is %=

S.I=2592

C.I== 432+432+216+72+36+36+6 = 1230

Difference between C.I and S.I = C.I – S.I = 1230-810=420