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.
Ab eth said:
3 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.
(26)
Gaurav said:
4 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%.
(24)
Pranshi said:
2 years ago
Why we didn't take 8/12 instead of 1? Please explain me.
(20)
Nijin said:
4 years ago
Shouldn't we change the number of years as 8/12 and 3/12 instead of 1? Anyone, please clarify.
(18)
Ayan said:
11 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.
(15)
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)
Tom and Jerry said:
12 months ago
How come 2175? Please explain.
(10)
Nias said:
3 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)
Rachana M R said:
4 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.
(7)
SIDDHARTH said:
4 years ago
@SOHAM.
NO, we should not take 2/3(YEAR) i.e 8 MONTHS.
BECAUSE the one who have borrowed the money have returned the money only after a year not in the middle i.e is 8 months so we considered it as a year and not as 2/3.
NO, we should not take 2/3(YEAR) i.e 8 MONTHS.
BECAUSE the one who have borrowed the money have returned the money only after a year not in the middle i.e is 8 months so we considered it as a year and not as 2/3.
(6)
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