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:
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 5 of 5.
Mercy said:
1 decade ago
Simpler yet old-fashioned solution to me would be:
30000*7/100=2100 - year 1
30000+2100=32100*7/100=2247 - year 2
now add 2100+2247=4347 which was the compound interest earned after 2years.
Thus the ans is 2 years.
30000*7/100=2100 - year 1
30000+2100=32100*7/100=2247 - year 2
now add 2100+2247=4347 which was the compound interest earned after 2years.
Thus the ans is 2 years.
(1)
Anusha said:
1 decade ago
Amount=30000+4347 = 34347
amount=p(1+R/100)^n
34347=30000(1+7/100)^n
34347=30000(107/100)^n
34347/30000=(107/100)^n
11429/10000=(107/100)^n.
hence
(107/100)^2=11429/10000.
amount=p(1+R/100)^n
34347=30000(1+7/100)^n
34347=30000(107/100)^n
34347/30000=(107/100)^n
11429/10000=(107/100)^n.
hence
(107/100)^2=11429/10000.
Prabakaran said:
1 decade ago
What is 107/100 ?
Dittya said:
1 decade ago
Yaa, its because (107)^2 = 11449 and (100)^2 = 10000.
Lalitha said:
1 decade ago
Can any one please help how it has come (107/100)^2
Chaitu said:
1 decade ago
30000(107/100)=32100
(32100*7)/100=147 is for 1 year
2100+2100+147=4347
2 years
(32100*7)/100=147 is for 1 year
2100+2100+147=4347
2 years
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