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.
SUDHAKAR said:
9 years ago
In my way, the answer is 3.96.
Calculation....
Let orginal rate is =r%
After 8 months=2r%
Then,
The rate of whole one year+rate of after 8 months+rate of other rate=33.5.
725*R*8/12+362.5*2R*4/12+362.5*R*4/12=33.5.
R(725*2+725+362.5)=33.5*300(BECAUSE 1/3*100.
THEN
R=(335*30)/2537.5,
R=3.96.
Calculation....
Let orginal rate is =r%
After 8 months=2r%
Then,
The rate of whole one year+rate of after 8 months+rate of other rate=33.5.
725*R*8/12+362.5*2R*4/12+362.5*R*4/12=33.5.
R(725*2+725+362.5)=33.5*300(BECAUSE 1/3*100.
THEN
R=(335*30)/2537.5,
R=3.96.
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%.
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.
Ray said:
9 years ago
What is 2175 it should also 725, as 362.
50 * 2R *1 becomes 725
50 * 2R *1 becomes 725
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%.
Maya said:
9 years ago
I agree @Supriya.
I too get the answer as 4.5%.
I too get the answer as 4.5%.
Sudhanshu ranjan said:
9 years ago
Given explanation is right, it is easy to understand the problem now.
@hmed said:
9 years ago
Why we take 2175?
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.
Sandeep said:
9 years ago
Why r is taken as 2r? Explain.
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