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. |
|
|||||||||||||
|
||||||||||||||
| = 3972. |
Discussion:
94 comments Page 3 of 10.
Subash said:
2 decades ago
Please explain the use of -1 in C.I calculation. I think here we have to subtract the principle at the back. But u use the value '1' here, I can't understand Wat u r did.
But i got the same answer by using the formula.
C.I = (Amount - Principle)
Where
Amount = {P x (1 + (R/100)^N)} - P
P = 12000.
Therefore, C.I = Rs. (12000*(1+(10/100)^3))-12000 = 3972
But i got the same answer by using the formula.
C.I = (Amount - Principle)
Where
Amount = {P x (1 + (R/100)^N)} - P
P = 12000.
Therefore, C.I = Rs. (12000*(1+(10/100)^3))-12000 = 3972
(1)
Ganesh said:
7 years ago
@All.
1st find rate R of 6 yr Assume 100rs, for 6 yr.
R=(100 * s.i/p * n) = 10%.
After that find C.I using ratio proposition of 3 yr is 3:3:1 is fixed and 2yr is (2:1).
Then 1st yr c.i. is 3* 10% of 12000,
2nd yr C.I is 3* 10% of 1200,
3rd yr C.I is 1* 10% of 120 add all the yrs.
3600 + 360 + 12 = 3972 is the answer.
1st find rate R of 6 yr Assume 100rs, for 6 yr.
R=(100 * s.i/p * n) = 10%.
After that find C.I using ratio proposition of 3 yr is 3:3:1 is fixed and 2yr is (2:1).
Then 1st yr c.i. is 3* 10% of 12000,
2nd yr C.I is 3* 10% of 1200,
3rd yr C.I is 1* 10% of 120 add all the yrs.
3600 + 360 + 12 = 3972 is the answer.
(1)
Mohammad Gazali said:
8 years ago
Please tell me how R=100*60/100*6?
(1)
BLESSING said:
9 years ago
The formula for compound interest:.
A = P (1 + r) ^n.
Now, P = 12000.
A = ?
N = 3.
From the first statement, there was 60% increase in an amount for 6 years simple interest.
Let the amount (P) be 100 then SI=60, SI = PIN.
60 = 100 * I * 6,
60 = 600 I,
I = 0.1.
Since we have 0.1 x 100 = 10%.
Now A = 12000 (1 + 1/10)^3
= 12000 (11/10)^3,
= 12000 (11/10 x 11/10 x 11/10),
= 12000 (1331/1000) = 15,972.
So, A = 15972, P = 12000 then,
CI = 15972 - 12000 = 3972.
A = P (1 + r) ^n.
Now, P = 12000.
A = ?
N = 3.
From the first statement, there was 60% increase in an amount for 6 years simple interest.
Let the amount (P) be 100 then SI=60, SI = PIN.
60 = 100 * I * 6,
60 = 600 I,
I = 0.1.
Since we have 0.1 x 100 = 10%.
Now A = 12000 (1 + 1/10)^3
= 12000 (11/10)^3,
= 12000 (11/10 x 11/10 x 11/10),
= 12000 (1331/1000) = 15,972.
So, A = 15972, P = 12000 then,
CI = 15972 - 12000 = 3972.
(1)
Riya said:
8 years ago
helpful
AKASH KADAM said:
2 weeks ago
For simple interest, 60% for the 6 years.
So, for one year it is - 10 % p.a.
Now the principle amount is- 12000.
We have to calculate the compound interest for 3 years.
On the 10% per annum rate.
So for the first year it's - 1200.
For the second year it's - 1320.
For the third year, it's - 1452.
Now add all of them - 1200 + 1320 + 1452.
= 3972.
So, for one year it is - 10 % p.a.
Now the principle amount is- 12000.
We have to calculate the compound interest for 3 years.
On the 10% per annum rate.
So for the first year it's - 1200.
For the second year it's - 1320.
For the third year, it's - 1452.
Now add all of them - 1200 + 1320 + 1452.
= 3972.
Renu said:
9 years ago
10% successive of 3 years is 33.1%
33.1% of 12000.
= 3972.
33.1% of 12000.
= 3972.
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.
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.
Victor said:
9 years ago
Please help me to solve this question.
Formula:
Fp=Pp(1+r) raise to power n.
if Pp=100, r=3%,n = 10.
Formula:
Fp=Pp(1+r) raise to power n.
if Pp=100, r=3%,n = 10.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers