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. |
|
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|
||||||||||||||
| = 3972. |
Discussion:
94 comments Page 9 of 10.
Nivedita said:
1 decade ago
How you have taken P as 100 ?
Dron said:
9 years ago
How to find p=100?
Manisha said:
9 years ago
Thanks @Sanjay.
Sudarsan said:
9 years ago
Thanks @Neha.
Sanjay said:
9 years ago
60% is equal to 60/100 i.e., S.I means adding the same rate of interest every year, So here we knew that 60% is increased in 6 years, i.e., Every year it is increased by 10%.
Then, caculate net % for 3yrs.
i.e.
Calculte 1st (10%)and 2nd yr(10%).then result with 3rd yr(10%).
i.e 10+10+(10 * 10)/100 = 21.
Next 21+10+(21 * 10)/100 = 33.1%.
So now just calculate 33.1%12000.
i.e 3972.
Then, caculate net % for 3yrs.
i.e.
Calculte 1st (10%)and 2nd yr(10%).then result with 3rd yr(10%).
i.e 10+10+(10 * 10)/100 = 21.
Next 21+10+(21 * 10)/100 = 33.1%.
So now just calculate 33.1%12000.
i.e 3972.
Sammy said:
9 years ago
Thank you so much for explaining the solution.
Satya said:
1 decade ago
60% is equal to 60/100 i.e., S.I means adding same rate of interest every year, So here we knew that 60% is increased in 6 years, i.e., Every year it is increased by 10%.
So that 10% * 6 years= 60% for 6 years. So that rate of interest = 10%.
So that 10% * 6 years= 60% for 6 years. So that rate of interest = 10%.
Malinimadhavan said:
9 years ago
@Angad.
Formula to find the rate of interest from ci is r= n[(A/P)^1/nt -1].
Now take p=12000; amount (A) = C.I + PRINCIPLE (3972+12000) = 15972; time(t) = 3years n=1.
By substituting this values in the above equation.
r = 1[(15972/12000)^1/3 -1],
= [(1.331)^1/3 -1],
r = [1.1-1],
r = 0.1.
To calculate rate of interest in percentage we use R = r*100.
Therefore R = 0.1*100 = 10%.
Thus rate of interest is 10% p.a.
I hope it will help you.
Formula to find the rate of interest from ci is r= n[(A/P)^1/nt -1].
Now take p=12000; amount (A) = C.I + PRINCIPLE (3972+12000) = 15972; time(t) = 3years n=1.
By substituting this values in the above equation.
r = 1[(15972/12000)^1/3 -1],
= [(1.331)^1/3 -1],
r = [1.1-1],
r = 0.1.
To calculate rate of interest in percentage we use R = r*100.
Therefore R = 0.1*100 = 10%.
Thus rate of interest is 10% p.a.
I hope it will help you.
Angad said:
9 years ago
How to find the rate of interest if compound interest and principle and time is already given but the rate is missing? I need the solution.
Renu said:
9 years ago
10% successive of 3 years is 33.1%
33.1% of 12000.
= 3972.
33.1% of 12000.
= 3972.
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