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 6 of 10.
Dorji Tshering said:
4 years ago
How comes after 8 months = 1/3 months?
I think 12 - 8 = 4, so we have to calculate the interest amount of the second amount for 1/4months.
I think 12 - 8 = 4, so we have to calculate the interest amount of the second amount for 1/4months.
(4)
Yash said:
9 years ago
Don't consider that the money is being lent to the same person. Take different persons. So it will be different for 8 months and 4 months.
Uma said:
9 years ago
725 =p, t = 12m.
pr * 8 + (1/2)p * 2r * 4 = 33.50 * 100.
8pr + 4pr = 3350,
12pr = 3350,
prt = 3350,
725 * r * 1 = 3350,
r = 4.5%.
pr * 8 + (1/2)p * 2r * 4 = 33.50 * 100.
8pr + 4pr = 3350,
12pr = 3350,
prt = 3350,
725 * r * 1 = 3350,
r = 4.5%.
Himal said:
8 years ago
I think correct answer is 2.77...725 is only for 8 months/for the next four month a total of 725 + 362.5 is under consideration.
NAVEENKUMAR said:
8 years ago
In the question, it's mentioned the interest is per annum hence we need to take T as 2/3 in first case & 1/3 in the second case.
Mansalal said:
7 years ago
After 8 months, the principal should be 725+362.50, but it cannot be just 362.50.
Can you justify why is it just 362.50?
Can you justify why is it just 362.50?
Dolagobinda behera said:
1 decade ago
I agreed to @Tarun as the way he approached the question. I think the answer might be wrong as explained in the answer.
Hemed said:
9 years ago
Because question says, after 8 months means the interest of last four months is twice or double the previous one.
Rajni Bala said:
8 years ago
Here, the original rate is for 1 year(s); the new rate is for only 4 months i.e. year(s). Please explain this.
Ujwal said:
9 years ago
The actual expression should be:
(725x2/3xR/100)+(1087.5x1/3x2R/100) = 33.5,
i.e. R=10050/3634 = 2.77%.
(725x2/3xR/100)+(1087.5x1/3x2R/100) = 33.5,
i.e. R=10050/3634 = 2.77%.
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