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 5 of 10.
Sudhanshu ranjan said:
9 years ago
Given explanation is right, it is easy to understand the problem now.
Maya said:
9 years ago
I agree @Supriya.
I too get the answer as 4.5%.
I too get the answer as 4.5%.
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%.
Ray said:
9 years ago
What is 2175 it should also 725, as 362.
50 * 2R *1 becomes 725
50 * 2R *1 becomes 725
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.
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%.
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.
GARIMA said:
8 years ago
Why multiplying it with 1/3?
Please explain.
Please explain.
Rajnish said:
8 years ago
I didn't understand this problem, so please solve this problem simply.
(1)
Indramani said:
8 years ago
I didn't took that 4-month interest concept. suppose x is the interest per year, so per month, it will be x/12.
So then ((725*8*x) / (100*12)) + ((362.5*4*2x) / (100*12)) = 33.5.
Solving this gives x = 4.62.
So then ((725*8*x) / (100*12)) + ((362.5*4*2x) / (100*12)) = 33.5.
Solving this gives x = 4.62.
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