Aptitude - Compound Interest - Discussion
Discussion Forum : Compound Interest - General Questions (Q.No. 14)
14.
The difference between compound interest and simple interest on an amount of Rs. 15,000 for 2 years is Rs. 96. What is the rate of interest per annum?
Answer: Option
Explanation:
 |
15000 x |  |
1 + | R |  |
2 | - 15000 |  |
- | |
15000 x R x 2 | |
= 96 | |
| 100 | 100 |
 15000 |
|
|
1 + | R | |
2 | - 1 - | 2R | |
= 96 |
| 100 | 100 |
| 15000 |
 |
(100 + R)2 - 10000 - (200 x R) |  |
= 96 |
| 10000 |
| R2 = |
|
96 x 2 | |
= 64 |
| 3 |
R = 8.
Rate = 8%.
Discussion:
32 comments Page 3 of 4.
Somnath said:
8 years ago
@Prawin and @Velavan.
Thank you very much for giving the simple trick for the solution.
Thank you very much for giving the simple trick for the solution.
Rahul said:
8 years ago
What will be solution, if time is 3years?
Anisa said:
7 years ago
Here 100^3*(CI-SI)/R^2(R+300).
Upasana said:
7 years ago
Can the difference be added to the principal to get the amount for compound interest formula?
And then by using CI formula rate can be calculated.
And then by using CI formula rate can be calculated.
Wrick said:
7 years ago
Simply, the solution is;
15000 * [{1+(r/100)}^2-1]-(15000 * 2 * r)/100 = 96,
=> 15000[{1+(r/100)}^2-1-(2 * r)/100]= 96,
=> 15000[1+(r^2)/10000-1] = 96 where [(a+b)^2-2ab = a^2 + b^2],
=> 15000[r^2/10000] = 96,
=> r^2 = 64,
=> r = 8.
15000 * [{1+(r/100)}^2-1]-(15000 * 2 * r)/100 = 96,
=> 15000[{1+(r/100)}^2-1-(2 * r)/100]= 96,
=> 15000[1+(r^2)/10000-1] = 96 where [(a+b)^2-2ab = a^2 + b^2],
=> 15000[r^2/10000] = 96,
=> r^2 = 64,
=> r = 8.
(2)
Himani said:
6 years ago
Simply:
sum = difference * (100/R)^2 for 2 year.
sum = {difference * (100^3)}/{R^2*(300+R)} for 3 year.
sum = difference * (100/R)^2 for 2 year.
sum = {difference * (100^3)}/{R^2*(300+R)} for 3 year.
(1)
Tamalika Roy said:
5 years ago
@All.
The solution is;
Difference = sum(R/100)^n => formula.
Here;
96 = 15000(r/100)^2 = 8.
The solution is;
Difference = sum(R/100)^n => formula.
Here;
96 = 15000(r/100)^2 = 8.
(1)
Siddu said:
5 years ago
P = si-ci/(r/100) 2 use this formula to get the answer.
Khyati mehta said:
4 years ago
We can directly do this by using the formula.
Difference between SI and CI for 2 years = principle *(Rate of Interest)^2
= P(R%)^2.
So here the difference is 96, principle=15000.
96 = 15000*(R/100)^2.
r = 8%.
Difference between SI and CI for 2 years = principle *(Rate of Interest)^2
= P(R%)^2.
So here the difference is 96, principle=15000.
96 = 15000*(R/100)^2.
r = 8%.
(1)
Naveen said:
4 years ago
CI-SI = P(R/100)^2.
CI-SI = 96.
P = 15000.
96 = 15000(R/100)^2,
96/15000 = R^2/100^2,
0.0064 = R^2/10000,
64 = R^2,
R = 8.
CI-SI = 96.
P = 15000.
96 = 15000(R/100)^2,
96/15000 = R^2/100^2,
0.0064 = R^2/10000,
64 = R^2,
R = 8.
(7)
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