Aptitude - Compound Interest - Discussion

Discussion Forum : Compound Interest - General Questions (Q.No. 3)
3.
There is 60% increase in an amount in 6 years at simple interest. What will be the compound interest of Rs. 12,000 after 3 years at the same rate?
Rs. 2160
Rs. 3120
Rs. 3972
Rs. 6240
None of these
Answer: Option
Explanation:

Let P = Rs. 100. Then, S.I. Rs. 60 and T = 6 years.

R = 100 x 60 = 10% p.a.
100 x 6

Now, P = Rs. 12000. T = 3 years and R = 10% p.a.

C.I.
= Rs. 12000 x 1 + 10 3 - 1
100
= Rs. 12000 x 331
1000
= 3972.

Discussion:
94 comments Page 4 of 10.

Aparna said:   1 decade ago
How could it come 331/1000? Shall anyone explain me please?

Hari said:   1 decade ago
How to find p=100?

Rohani said:   1 decade ago
Why we take S.I as 60 and what is the difference between S.I and C.I?

Aditya said:   10 years ago
S.I is interest on Principle.

C.I is interest of interest.

Beaulah abigail said:   10 years ago
How the formula C.I = Amount-P comes?

Rahul said:   10 years ago
Brother the answer should be 3852 and a simpler method could be 10 percent of 12000 = 1200 + 10% of 12000 + 10% of 1200 = 1200 + 120 and so on the last will be 1200 + 120 + 12 so grand total 3852.

Prasad said:   10 years ago
Sir question says there is an increase of 60% in amount. How can you take 60 as SI?

Pavan said:   10 years ago
I am getting confusion on this problem can anyone tell me in easy way.

Lee Chong Wei said:   10 years ago
Hi can anyone explain me why CI = Amount-P if its P we can substitute the actual principal.

Dearlie Beloved said:   10 years ago
'I' means increase, since I=F-P. Taking 60 as SI while letting P=100 in i=I/Pn assumes that the future amount will be 60 greater than 100.

We can let P as any number, say P=210, but we need to change I=150 to signal 60 in increase of future amount. We only put P=100 to give justice to the percent sign after 60.

And compound interest is what was asked and not CI rate? Hope this helped.


Post your comments here:

Your comments will be displayed after verification.