Aptitude - Compound Interest - Discussion
Discussion Forum : Compound Interest - General Questions (Q.No. 15)
15.
The compound interest on a certain sum for 2 years at 10% per annum is Rs. 525. The simple interest on the same sum for double the time at half the rate percent per annum is:
Answer: Option
Explanation:
Let the sum be Rs. P.
| Then, |  |
P |  |
1 + | 10 |  |
2 | - P |  |
= 525 |
| 100 |
 |
P | |
|
11 | |
2 | - 1 | |
= 525 |
| 10 |
| P = |
|
525 x 100 | |
= 2500. |
| 21 |
Sum = Rs . 2500.
| So, S.I. = Rs. | |
2500 x 5 x 4 | |
= Rs. 500 |
| 100 |
Discussion:
37 comments Page 3 of 4.
Mounika said:
9 years ago
Is there any shortcut way to solve this problem? If yes means please share.
Vibhanshu said:
1 decade ago
Actually 525/21=25
Vidhur said:
1 decade ago
@sandy
Given that 525 is the CI calculated for 2 years at a rate of 10%. so, 525 is the difference of ((P+CI)-(p)). where "p" is the principle amount.
Did you get sandy?
Given that 525 is the CI calculated for 2 years at a rate of 10%. so, 525 is the difference of ((P+CI)-(p)). where "p" is the principle amount.
Did you get sandy?
Hemant said:
1 decade ago
I am confused that why we are taking -p. Can you explain me ?
Balu said:
1 decade ago
I am not getting why they have taken -p? can any one explain pls..?
Sikun said:
1 decade ago
CI=Amount-Principle.
And we know the CI, but don't know Principle. So to find P we are subtracting P.
And we know the CI, but don't know Principle. So to find P we are subtracting P.
Varalaksmi said:
1 decade ago
Hai I think this way may be correct for finding the value of p.
p = (121/100-1).
p = (121-100/100).
p = (21/100).
p = (21/100) = Rs.525.
So, p = (525*100)/21.
p = Rs.2500.
p = (121/100-1).
p = (121-100/100).
p = (21/100).
p = (21/100) = Rs.525.
So, p = (525*100)/21.
p = Rs.2500.
Anonymus said:
1 decade ago
Guys its very simple.
Use net effect for calculating the interest, equate it to the CI given and find the principle amount. The only thing is you should be knowing how to use net effect.
Use net effect for calculating the interest, equate it to the CI given and find the principle amount. The only thing is you should be knowing how to use net effect.
Manjeet said:
1 decade ago
Still I am not get how this (-p) is came from? kindly suggest.
Kapricious said:
8 years ago
As they are saying 10% per annum and 2 years in time, we can be sure that Rs 21 gained as interest for Rs 100 in 2 years.
So, C.I is 21 when Principal is 100.
if C.I equal 525, the principal will be (100 * 525)/21.
= 2500.
So, C.I is 21 when Principal is 100.
if C.I equal 525, the principal will be (100 * 525)/21.
= 2500.
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