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 3 of 15.
Kurdush said:
4 years ago
Shortcut to solve :
(100*100*Diff)/Rate * Rate.
here diff =1.
rate=4.
Substitute in above formula u get Rs.625.
(100*100*Diff)/Rate * Rate.
here diff =1.
rate=4.
Substitute in above formula u get Rs.625.
(5)
Madhav said:
5 years ago
Hi.
Before solving this question you have to be aware on S.I and C.I formula's.
S.I = PTR/100.
Where as AMOUNT = P (1+ R/100) ^T ====> IN C.I.
AMOUNT = P + C.I.
C.I = P (1+ R/100) ^T - P.
In the question, they give the difference between S.I AND C.I is rupee 1.
First Calculate S.I.
Let the PRINCIPAL or SUM be ==> '' P '', TIME = 2, RATE = 4%.
S.I = PTR/100 ==> P*2*4/100 ==> 2P/25.
Now C.I = P (1+R/100) - P ==> P (1+4/100) - P ==> 51P/625.
51P/625 - 2P/25 = 1.
LCM IS 625.
51P - 50P/625 = 1.
P = 625.
I hope this will be helpful.
Thank you.
Before solving this question you have to be aware on S.I and C.I formula's.
S.I = PTR/100.
Where as AMOUNT = P (1+ R/100) ^T ====> IN C.I.
AMOUNT = P + C.I.
C.I = P (1+ R/100) ^T - P.
In the question, they give the difference between S.I AND C.I is rupee 1.
First Calculate S.I.
Let the PRINCIPAL or SUM be ==> '' P '', TIME = 2, RATE = 4%.
S.I = PTR/100 ==> P*2*4/100 ==> 2P/25.
Now C.I = P (1+R/100) - P ==> P (1+4/100) - P ==> 51P/625.
51P/625 - 2P/25 = 1.
LCM IS 625.
51P - 50P/625 = 1.
P = 625.
I hope this will be helpful.
Thank you.
(35)
Mohit said:
5 years ago
How 51/625x came? Please explain.
(3)
Sumit said:
5 years ago
Diff = p(R/100) ^n.
By using this formula you can directly find the amount i.e. p.
1=p(4/100) ^2.
=> p=625.
By using this formula you can directly find the amount i.e. p.
1=p(4/100) ^2.
=> p=625.
(3)
Verma said:
5 years ago
Use this to get the answer.
Sum = X(100/r)^2.
where X = C.I - S.I.
Sum = X(100/r)^2.
where X = C.I - S.I.
(1)
Mithra said:
5 years ago
Excellent. Thanks all for explaining.
Anju Chimouriya said:
6 years ago
Why cannot we use the compound interest formula in this problem?
Yogesh patil said:
6 years ago
One of the simplest way to solve difference between si and ci by using simple formula
Diff=PR^2/100^2.
Diff=1*4^2/100*100.
Diff=1/625.
Ans=625.
Diff=PR^2/100^2.
Diff=1*4^2/100*100.
Diff=1/625.
Ans=625.
(1)
Yogesh patil said:
6 years ago
One of the simplest way to solve difference between si and ci by using simple formula
Diff=PR^2/100^2.
Diff=1*4^2/100*100.
Diff=1/625.
Ans=625.
Diff=PR^2/100^2.
Diff=1*4^2/100*100.
Diff=1/625.
Ans=625.
Yogesh patil said:
6 years ago
One of the simplest way to solve difference between si and ci by using simple formula
Diff=PR^2/100^2.
Diff=1*4^2/100*100.
Diff=1/625.
Ans=625.
Diff=PR^2/100^2.
Diff=1*4^2/100*100.
Diff=1/625.
Ans=625.
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