# Compound Interest Part 7

Compounded half-yearly, then rate=$\frac{r}{2}$% and time=2*time

Compounded quarterly, then rate=$\frac{r}{4}$% and time=4*time

Problem1: The compound interest earned on a sum in 3 years at 15% per annum compounded annually is RS.25002. Find the sum?

Solution: R=15%  Time=3 year C.I=25002

1200*3=3600

180*3=540

3600+540+27=4167

4167——>25002

8000——–>?

$\frac{25002\times&space;8000}{6}=48000$ is principle

Problem 2: A sum of RS.19600 is invested at 20% rate of compound interest for 2 years compounded half yearly. then the end of two years compound interest will be how much more than the S.I?

Solution:

Rate=$\frac{20}{2}=10$%  time =2*2=4 years

we will split 4 years into 2 and 2 years

R=10% T=2 years

C.I=10+10+$\frac{10\times&space;10}{100}=21$%

R=21% T=2 years

21+21+$\frac{21\times&space;21}{100}=21+21+4.41=46.41$%

C.I=46.41%

S.I=10*4=40%

46.41-40=6.41%

100%———>19600

6.41%———->?

$\frac{19600\times&space;6.41}{100}=1256.36$

Problem 3: If a sum of Rs.3600 is invested in two different banks for 2 years first offering 20% compound interest compounded annually and second offer 20% compounded half yearly then find the difference of the interest after 2 years?

Solution:

first offering 20% compound interest compounded annually

20%———-C.I———-Annually

20+20+$\frac{20\times&space;20}{100}$ = 44%

second offer 20% compounded half yearly

Rate=$\frac{20}{2}=10$%  , Time=2*2=4 years

10+10+$\frac{10\times&space;10}{100}$=21%

21+21+$\frac{21\times&space;21}{100}$=46.41%

46.41 – 44=2.41%

100%———->3600

2.41%———>?

$\frac{3600\times&space;2.41}{100}$=86.76