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?
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. |
|
|||||||||||||
|
||||||||||||||
| = 3972. |
Discussion:
94 comments Page 8 of 10.
Javeed said:
2 decades ago
Dude here principle is Rs. 12000, so amount = P(1+r/100)^t
C.I = amount - principle i.e., p((1+r/100)^t )-p
Removing 'p' common factor we get:
p((1+(R/100)^T)-1)
HERE 1200 IS REMOVED AS COMMON FACTOR SINCE IT IS THE VALUE OF P.
C.I = amount - principle i.e., p((1+r/100)^t )-p
Removing 'p' common factor we get:
p((1+(R/100)^T)-1)
HERE 1200 IS REMOVED AS COMMON FACTOR SINCE IT IS THE VALUE OF P.
Beaulah abigail said:
10 years ago
How the formula C.I = Amount-P comes?
Malleswar said:
9 years ago
Beautifully explained. Thanks to all.
Prabhakaran said:
9 years ago
Hi, can anyone explain to me why CI = Amount - P if its P we can substitute the actual principal.
Vikash said:
9 years ago
After taking common factor p from bracket then automatically -1 come i.e. -1 * p = -p.
If you are confused about -1 then don't take common answer come same but it becomes some complicated.
If you are confused about -1 then don't take common answer come same but it becomes some complicated.
Thejus said:
9 years ago
@Josephlecocq.
What is -1 as p?
What is -1 as p?
Durga said:
9 years ago
@ All, Guys your discussions are very useful. Thank you all.
Vani said:
10 years ago
Suppose principle is 100.
Then simple interest becomes 60.
Then rate will become 10% by using the formula,
(ptr)/100 = simple interest.
Now the compound interest in 3 years with the rate 10% is,
10+10+1(interest on interest)+11+1.1 = 33.1.
12000 --- 100
?----------- 33.1
The answer is 3972.
Then simple interest becomes 60.
Then rate will become 10% by using the formula,
(ptr)/100 = simple interest.
Now the compound interest in 3 years with the rate 10% is,
10+10+1(interest on interest)+11+1.1 = 33.1.
12000 --- 100
?----------- 33.1
The answer is 3972.
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.
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.
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.
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