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 1 of 10.
Jay said:
2 years ago
From Where this -1 came? Please explain to me.
(24)
Shima said:
1 year ago
For 6 years = 60% increase.
i.e for 1 year = 10% pa.
i.e for 1 year = 10% pa.
(21)
Rajdeep saha said:
2 years ago
C.I = {12,000(1+10/100)^3} - 12000.
=3,972 => (answer).
=3,972 => (answer).
(19)
Nishu said:
2 years ago
@All
Here, -1 came from the formula of compound interest as;
C.I = Amount - Principal.
Here, -1 came from the formula of compound interest as;
C.I = Amount - Principal.
(17)
Katherin said:
5 years ago
I'm confused on using -1. Why it is used?
Please anyone explain.
Please anyone explain.
(16)
Shivani Nikam said:
12 months ago
-1 because they have taken P common.
(15)
Vattikuti shivaram said:
2 years ago
We can solve in a simple way also if we have 12000 as the principal amount then we can.
Divide with a 10% rate
By dividing 12000. With we get 1200 in three times because of three years of interest as SI;
And now doing 1200 we get 3 times 120 for three years CI
We know that ci is recursive with year one 120 divided by 1/10
Then we get 12;
Now 3*1200+3*120+12 = 3972.
Divide with a 10% rate
By dividing 12000. With we get 1200 in three times because of three years of interest as SI;
And now doing 1200 we get 3 times 120 for three years CI
We know that ci is recursive with year one 120 divided by 1/10
Then we get 12;
Now 3*1200+3*120+12 = 3972.
(14)
Sai said:
5 years ago
12000 in 10% is 1200.
So 1st year 12000+1200 = 13200.
13200 in 10 % is 1320 so 13200 + 1320 = 14520.
Next 3rd year 14520 in 10% is 1452 so, 14520 + 1452 = 15972.
So, finally 15972 - 12000 = 3972.
So 1st year 12000+1200 = 13200.
13200 in 10 % is 1320 so 13200 + 1320 = 14520.
Next 3rd year 14520 in 10% is 1452 so, 14520 + 1452 = 15972.
So, finally 15972 - 12000 = 3972.
(13)
Pratiksha said:
5 years ago
@Katherin,
Instead of -1 you can take principal amount( in this case -12000/-), you will get the same answer.
Instead of -1 you can take principal amount( in this case -12000/-), you will get the same answer.
(8)
Gaichalung kamei said:
2 years ago
160% increase..
160/100 = 8/5.
Let's assume 5 is the amount.
60% increase of 5 gives 8. There is a difference of 3 between 5 and 8. The given period is 6 yrs.
So, 6/3 = 2.
Now we can calculate the rate.
P × R × T/100 = 5 × R × 2/100 which gives 10%.
Now compound interest for 3 yrs with the same rate.
(11/10)³= 1331/1000.
The given principle is 12000. We get 12 as a multiplying factor.
now, CI = 331×12 = 3972.
160/100 = 8/5.
Let's assume 5 is the amount.
60% increase of 5 gives 8. There is a difference of 3 between 5 and 8. The given period is 6 yrs.
So, 6/3 = 2.
Now we can calculate the rate.
P × R × T/100 = 5 × R × 2/100 which gives 10%.
Now compound interest for 3 yrs with the same rate.
(11/10)³= 1331/1000.
The given principle is 12000. We get 12 as a multiplying factor.
now, CI = 331×12 = 3972.
(6)
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