Aptitude - Compound Interest - Discussion

Discussion Forum : Compound Interest - General Questions (Q.No. 5)
5.
The compound interest on Rs. 30,000 at 7% per annum is Rs. 4347. The period (in years) is:
2
2 1
2
3
4
Answer: Option
Explanation:

Amount = Rs. (30000 + 4347) = Rs. 34347.

Let the time be n years.

Then, 30000 1 + 7 n = 34347
100

107 n = 34347 = 11449 = 107 2
100 30000 10000 100

n = 2 years.

Discussion:
46 comments Page 3 of 5.

France said:   9 years ago
107 * 107 is 11449 and 100 * 100 = 10000 but how is it equal to 34347/30000 ?

Anurag Nath said:   9 years ago
@Hitendra.

(107/100)n = 11449/10000.
=> 107 * 107/100 * 100 = 11449/10000.
=> (107/100)2 = 11449/10000 [Here n = 2].

Therefore n=2.

Dearlie Beloved said:   10 years ago
Shortcut through using ln:

t = ln (34 347/30 000)/ln (1.07).
t = 2 years.

Abhilok said:   10 years ago
2 times in 10 years.
2^3 = 8 times in 3*10 = 30 years.

Let power = n.
Given year = y.
n*y is the answer.
(1)

Leo said:   10 years ago
Can anyone explain me the simplification of (107/100)2?

Bhabani said:   10 years ago
A sum becomes double in ten years in C.I. So in how many years the principal would be 8 times?

Trilok said:   10 years ago
11449/10000 = (107/100)^n , 1.1442 = (1.07)^n.

We can write as log 1.1442 = n log 1.07, n = log 1.1442/log 1.07 = 0.058501/0.029383 = 2 (as per scientific calculator).

Isha sharma said:   1 decade ago
Guys this is simple divide numerator and denominator by 3 you will get your answer.

Digvijay said:   1 decade ago
Ya! it's not easy to find out. We have to try with value of t.

TEJAS said:   1 decade ago
Why 34347/30000?


Post your comments here:

Your comments will be displayed after verification.