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 2 of 5.

Anomie said:   7 years ago
How did come 11449?
(1)

Bimla jarmwal said:   7 years ago
Please, anyone, explain the answer in detail to me.
(1)

Abhilok said:   1 decade 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)

Prasad said:   8 years ago
Why we square that 107/100 n=2? why? please.
(1)

Priya said:   8 years ago
What is 107/100? I can't understand, please explain.
(1)

Dearlie Beloved said:   1 decade ago
Shortcut through using ln:

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

Rkh said:   9 years ago
What if the power is( 107/100)^4?.

How can we find quad root of a number?

Chloe said:   9 years ago
Use the formula

n = [ log(fv/p) ] / [ log (1+i)].

Where
FV = future value.
P = present value.
i = interest ( in dec. place).

n = [ log ( 34,347/30,000) ] / [ log (1+0.07)].
= 2.

France said:   10 years ago
107 * 107 is 11449 and 100 * 100 = 10000 but how is it equal to 34347/30000 ?

B. Tatung said:   9 years ago
How come 3 divided by both numerator and denominator?

Please, someone, explain me.


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