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:
625
630
640
650
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 9 of 15.

Bunny_xavi said:   8 years ago
(R/100)^2= D/P
D=difference bw si and ci.
100^2/4*4 = 1/P.
P= 10000/16 =>625.

Sagy said:   10 years ago
I did not understand this sum please help give me a simple way to solve this sum.

Eshwar said:   10 years ago
CI = A-P.

A = P(1+r/100)n.

CI = P(1+r/100)n-P.

Where in above problem P = x.

Balaji said:   2 years ago
CI - SI = P(R/100)^2,
1 = P(4/100)^2,
1 = P(1/25)^2,
1 = P /625.
625 = P.
(40)

Pratik patel said:   1 decade ago
But. It is for only two years. I think. Not for 4;5;6 years. Try it. @Chetan.

Santhosh P said:   10 years ago
Difference for 2 years = P*(R/100)^2.

=> P*(4/100)^2 = 1.

=> P = 625.

Amit said:   9 years ago
Principal for two years = pr2/100*100.

Three years = pr2(300+r)/100*100*100.

Revant Borawat said:   9 years ago
Assume principal 100.

Then, CI=8.16 & SI=8.00,
1÷ 0.16 * 100 = 625.

Hema said:   1 decade ago
Shortcut formula P = (100/R)^T*D, D = Difference here.

= (100/4)^2*1 = 625.

Manjunath Reddy said:   9 months ago
@All.

Principle = difference(100/r)^2.
=> p = 1(100/4)^2 = (25)^2 = 625.
(11)


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