Aptitude - Compound Interest - Discussion
Discussion Forum : Compound Interest - General Questions (Q.No. 2)
2.
The difference between simple and compound interests compounded annually on a certain sum of money for 2 years at 4% per annum is Re. 1. The sum (in Rs.) is:
Answer: Option
Explanation:
Let the sum be Rs. x. Then,
| C.I. = |  |
x |  |
1 + | 4 |  |
2 | - x |  |
= | |
676 | x | - x | |
= | 51 | x. |
| 100 | 625 | 625 |
| S.I. = | |
x x 4 x 2 | |
= | 2x | . |
| 100 | 25 |
 |
51x | - | 2x | = 1 |
| 625 | 25 |
x = 625.
Discussion:
149 comments Page 6 of 15.
Tamanna said:
1 decade ago
How we got 51/625? can any one explain ?
Dew said:
1 decade ago
@Tamana.
Hey its simple sum just Few steps,
Step 1:
Compound interest = p(1+R/100)^n - p.
[Here p is subtracted from total amount at end of annum to find out compound interest].
Step 2:
Simple interest= pRn/100.
So,
Compound interest - simple interest = 1 Rs.
p(1+R/100)^n - p - pRn/100 = 1.
p(1+4/100)^2 - p - p*4*2/100 = 1.
p(1.04)^2 - p - p*.08 = 1.
p(1/625) = 1.
So p= 625 Answer.
Hey its simple sum just Few steps,
Step 1:
Compound interest = p(1+R/100)^n - p.
[Here p is subtracted from total amount at end of annum to find out compound interest].
Step 2:
Simple interest= pRn/100.
So,
Compound interest - simple interest = 1 Rs.
p(1+R/100)^n - p - pRn/100 = 1.
p(1+4/100)^2 - p - p*4*2/100 = 1.
p(1.04)^2 - p - p*.08 = 1.
p(1/625) = 1.
So p= 625 Answer.
Ravi said:
1 decade ago
Let's 100.
Simple interest = 100*2*4/100 = 8.
Total amount = 108.
Now find CI = 100*4/100 = 4.
104*4/100 = 4.16.
total = 108.16.
SI - CI = 108-108.16 = .16
1*100/.16 = 625.
Simple interest = 100*2*4/100 = 8.
Total amount = 108.
Now find CI = 100*4/100 = 4.
104*4/100 = 4.16.
total = 108.16.
SI - CI = 108-108.16 = .16
1*100/.16 = 625.
MANAS BISWAL said:
1 decade ago
(C.I)2 - (S.I)2 = 1.
SUCCESSIVE DISCOUNT(C.I) = 4+4(4*4/100) = 8.16.
(S.I) 4+4 = 8.
8.16-8 = 0.16 .
0.16/1*100 = 625.
SUCCESSIVE DISCOUNT(C.I) = 4+4(4*4/100) = 8.16.
(S.I) 4+4 = 8.
8.16-8 = 0.16 .
0.16/1*100 = 625.
Chetan siyota said:
1 decade ago
Short trick if you have given difference between simple and compound interest,
SI-CI = P*square of (R/100).
SI-CI = P*square of (R/100).
Pratik patel said:
1 decade ago
But. It is for only two years. I think. Not for 4;5;6 years. Try it. @Chetan.
Subhani said:
1 decade ago
Difference D = P(R*R)/10000.
Siva nandi reddy said:
1 decade ago
For 3 years p=(d*100*100*100)/(r*r(r+300)).
Amit kumar said:
1 decade ago
Sum = difference(100/rate)^t (here t=2yrs).
Sum = 1(100/4)^2 = 625.
Sum = 1(100/4)^2 = 625.
Tarakeswararao said:
1 decade ago
Hello friend this is Tarak.
Now we have formula for finding this type of problems.
i.e D = P*(R/100)^2 if the time is 2 years.
If time is 3 years now the formula is D = P*(R/100)^2*(3+(R/100)).
Where D = Difference.
P = Principle amount.
R = Interest.
Now we have formula for finding this type of problems.
i.e D = P*(R/100)^2 if the time is 2 years.
If time is 3 years now the formula is D = P*(R/100)^2*(3+(R/100)).
Where D = Difference.
P = Principle amount.
R = Interest.
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