Aptitude - Compound Interest - Discussion
Discussion Forum : Compound Interest - General Questions (Q.No. 7)
7.
At what rate of compound interest per annum will a sum of Rs. 1200 become Rs. 1348.32 in 2 years?
Answer: Option
Explanation:
Let the rate be R% p.a.
| Then, 1200 x |  |
1 + | R |  |
2 | = 1348.32 |
| 100 |
 |
|
1 + | R | |
2 | = | 134832 | = | 11236 |
| 100 | 120000 | 10000 |
 |
|
1 + | R | |
2 | = | |
106 | |
2 |
| 100 | 100 |
| 1 + |
R | = | 106 |
| 100 | 100 |
R = 6%
Discussion:
41 comments Page 3 of 5.
Charu said:
9 years ago
This method will take time because we need to think the square root that number. There is one formula for rate and i.e. 2 * ci - si * 100/si. But in this question how we'll able to find si?
(1)
Vijay said:
9 years ago
1348.32 is not the C.I.
It is the amount so obviously 1348.32 =1200(1 + r/100)^2,the formula for the amount,I got confused at this. Please help me.
It is the amount so obviously 1348.32 =1200(1 + r/100)^2,the formula for the amount,I got confused at this. Please help me.
(3)
Rakesh sharma said:
9 years ago
(100 + R) x 1200/100 = 1348.32,
100 + R = 1348.32 x 100/1200,
100 + R = 112.36,
R =12.36 * 6 + 6 + (6x6/100) = 12.36 so ans is 6.
100 + R = 1348.32 x 100/1200,
100 + R = 112.36,
R =12.36 * 6 + 6 + (6x6/100) = 12.36 so ans is 6.
Anilkumar said:
9 years ago
@Naresh it is divided by 12 since it is easy that way, also, it gives a perfect square of 106 & 100. One more important point you can divide both the numbers with any number, but we use specific numbers since they give a perfect square or else you can use any number to solve that problem.
Naresh said:
9 years ago
@Pinky.
You said that divide numerator and denominator by 12 we got 11236/10000.
My doubt is why we have to divide it by 12, please tell me the reason.
You said that divide numerator and denominator by 12 we got 11236/10000.
My doubt is why we have to divide it by 12, please tell me the reason.
Mounika said:
9 years ago
Please share short cut method for this type of problems.
TKB said:
10 years ago
Can't we just apply the formula P = R/T using 1200 as the principal amount?
Zahir said:
10 years ago
1348.32-1200 = 148.32.
Now, 148.32/1200*100 = 148.32/12 which is greater than 12% but less than 13%.
So for 2 years of effective compound interests, annual interest must be greater than 6% but less than 6.5% (as 6.5% would lead effective interest to somewhere greater than 13%).
So, given options answer must be 6%.
Answer: 6%.
Now, 148.32/1200*100 = 148.32/12 which is greater than 12% but less than 13%.
So for 2 years of effective compound interests, annual interest must be greater than 6% but less than 6.5% (as 6.5% would lead effective interest to somewhere greater than 13%).
So, given options answer must be 6%.
Answer: 6%.
Madhu said:
1 decade ago
How to find the root of 11236?
Narayana Rao Gartam said:
1 decade ago
Hai Shikhar,
1+R/100= 106/100.
100+R/100 = 106/100.
100+R= 106 ( 100 AND 100 CANCELLED EACH OTHER).
S0, R= 106-100.
i.e: 6.
I'm sure this would help you.
1+R/100= 106/100.
100+R/100 = 106/100.
100+R= 106 ( 100 AND 100 CANCELLED EACH OTHER).
S0, R= 106-100.
i.e: 6.
I'm sure this would help you.
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