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.
Sanjeev Sharma said:
9 years ago
We can always take base as 100.
On 100 CI for 2 yrs @10% = 21,
Now since CI is 525, therefore, P = 100 ÷ 21 * 525 = 2500,
Now SI = 2500 * 10 * 2 ÷ 100 = 500.
On 100 CI for 2 yrs @10% = 21,
Now since CI is 525, therefore, P = 100 ÷ 21 * 525 = 2500,
Now SI = 2500 * 10 * 2 ÷ 100 = 500.
R.b said:
9 years ago
Thank you, P.Kumar. Very well explained.
Chetana said:
9 years ago
Because they took p to be common @Tshering.
Tshering choden said:
9 years ago
Why did we subtract -1 in place of - p? I can't get this step, help me.
Kiran said:
9 years ago
Can anyone tell the simple form to get the value of p?
Mounika said:
9 years ago
Is there any shortcut way to solve this problem? If yes means please share.
P Kumar said:
1 decade ago
CI = Amount - Principle.
525 = Principle(1+10/100)^2 - Principle.
Rate = 10, Time = 2.
525 = Principle(110/100)^2 - Principle.
525 = Principle((22/20)^2-1)).
525 = Principle(121/100-1).
525 = Principle (21/100).
Principle = (525*100)/21.
Principle = 2500.
Now to calculate S.I principle = 2500 T=4 (double the time taken for C.I i.e 2*2 = 4).
R = 5 (Half of the rate taken for C.I i.e 10/2 = 5).
S.I = (P*T*R)/100.
S.I = (2500*4*5)/100.
S.I = 500.
525 = Principle(1+10/100)^2 - Principle.
Rate = 10, Time = 2.
525 = Principle(110/100)^2 - Principle.
525 = Principle((22/20)^2-1)).
525 = Principle(121/100-1).
525 = Principle (21/100).
Principle = (525*100)/21.
Principle = 2500.
Now to calculate S.I principle = 2500 T=4 (double the time taken for C.I i.e 2*2 = 4).
R = 5 (Half of the rate taken for C.I i.e 10/2 = 5).
S.I = (P*T*R)/100.
S.I = (2500*4*5)/100.
S.I = 500.
(1)
Manjeet said:
1 decade ago
Still I am not get how this (-p) is came from? kindly suggest.
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.
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.
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