Aptitude - Simple Interest - Discussion
Discussion Forum : Simple Interest - General Questions (Q.No. 9)
9.
A sum of Rs. 725 is lent in the beginning of a year at a certain rate of interest. After 8 months, a sum of Rs. 362.50 more is lent but at the rate twice the former. At the end of the year, Rs. 33.50 is earned as interest from both the loans. What was the original rate of interest?
Answer: Option
Explanation:
Let the original rate be R%. Then, new rate = (2R)%.
Note:
Here, original rate is for 1 year(s); the new rate is for only 4 months i.e. 
year(s).
 |
 |
725 x R x 1 |  |
+ | |
362.50 x 2R x 1 | |
= 33.50 |
| 100 | 100 x 3 |
(2175 + 725) R = 33.50 x 100 x 3
(2175 + 725) R = 10050
(2900)R = 10050
| R = |
10050 | = 3.46 |
| 2900 |
Original rate = 3.46%
Discussion:
97 comments Page 1 of 10.
Ayan said:
5 months ago
For 8 months take 2/3.
For 4 months take 1/3.
Then 725 * R * 2/100 * 3 + 362.50 * 2R * 1/100 * 3 = 4.62 approx. This is the correct solution.
For 4 months take 1/3.
Then 725 * R * 2/100 * 3 + 362.50 * 2R * 1/100 * 3 = 4.62 approx. This is the correct solution.
(4)
Tom and Jerry said:
6 months ago
How come 2175? Please explain.
(7)
Prakash c said:
1 year ago
1st amount of 725 is considered as 1 year amount then 2nd part of the amount is considered as 4 months interest. Then we will give the perfect answer.
(1)
Pranshi said:
1 year ago
Why we didn't take 8/12 instead of 1? Please explain me.
(15)
Akram said:
1 year ago
Why 2R/3 is coming in the second S.I formula, it should be 1/3 only,right?
(3)
Kiran said:
2 years ago
@All.
I Have 1 doubt. 1st He will be lent for 8 months or 1 year? Anyone, please explain me in detail.
I Have 1 doubt. 1st He will be lent for 8 months or 1 year? Anyone, please explain me in detail.
(12)
Nias said:
2 years ago
After 8 months means he is lent for the remaining 4 months within the year. In a simple way, someone can't lend for the previous time rather he lent for the future time.
Therefore, the result of 1/4 we can understand from this concept.
Therefore, the result of 1/4 we can understand from this concept.
(7)
Ab eth said:
2 years ago
Agee @Neha.
Because for 1 year we take 725 principal amount then it says 362.50 more after 8 months, for this reason, it must be 725 + 362.5 for the second principal.
Because for 1 year we take 725 principal amount then it says 362.50 more after 8 months, for this reason, it must be 725 + 362.5 for the second principal.
(22)
Rachana M R said:
3 years ago
@Nijin.
12 months =1 year,
4 months =?
On cross multiplication, we get 4/12 = 1/3.
12 months =1 year,
4 months =?
On cross multiplication, we get 4/12 = 1/3.
(6)
Gaurav said:
3 years ago
First amount given was Rs. 725, let the rate be R. A second amount was given i.e. Rs. 362.50 where rate is 2R.
Since it was given after 8 months, and the complete interest of both the amounts was taken together i.e. Rs.33.50.
So, time period for second amount for which the interest will be calculates will be 4 months that is 1/3 year.
Hence,
(725 * R * 1)/100 + (362.50*2R*1/3)/100 = 33.50,
=> 725R/100 + 725R/300 = 33.50,
=> (2175R+ 725R) / 300 = 33.50,
=> 2900R = 33.50*300,
=> R= 3.46%.
Since it was given after 8 months, and the complete interest of both the amounts was taken together i.e. Rs.33.50.
So, time period for second amount for which the interest will be calculates will be 4 months that is 1/3 year.
Hence,
(725 * R * 1)/100 + (362.50*2R*1/3)/100 = 33.50,
=> 725R/100 + 725R/300 = 33.50,
=> (2175R+ 725R) / 300 = 33.50,
=> 2900R = 33.50*300,
=> R= 3.46%.
(20)
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