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 3 of 10.
Shubham said:
6 years ago
How they take 725 for 1 year when the says the beginning of the year and after 8 months?
I think 725 is for 8/12 and 362.5 for 1/3.
Please suggest me.
I think 725 is for 8/12 and 362.5 for 1/3.
Please suggest me.
Laxmi kalouni said:
6 years ago
How 2175? Why multiplied by 3.
Please someone explain.
Please someone explain.
Sindu said:
6 years ago
3 * 725 = 2175.
Ashik said:
7 years ago
33.50 = ((R*725*8)/(100*12)) + ((2R*362.50*4)/(100*12)).
R = 6%.
R = 6%.
Ajay said:
7 years ago
(725*R*8/12)/100 + (725+362.5*2R*4/12)100 = 33.5,
(725*R*8/12)/100 + (1087.5*2R*4/12)/100 = 33.5,
(483.33 R)/100 + (725 R)/100 = 33.50,
(483.33 R) + (725 R) = 33.5*100,
1208.33 R = 3350,
R = 3350/1208.33,
R = 2.772.
(725*2.772*8/12)/100 = 13.398.
(1087.5*5.544*4/12)/100 = 20.097.
By adding, we get 33.495.
(725*R*8/12)/100 + (1087.5*2R*4/12)/100 = 33.5,
(483.33 R)/100 + (725 R)/100 = 33.50,
(483.33 R) + (725 R) = 33.5*100,
1208.33 R = 3350,
R = 3350/1208.33,
R = 2.772.
(725*2.772*8/12)/100 = 13.398.
(1087.5*5.544*4/12)/100 = 20.097.
By adding, we get 33.495.
(2)
Syed said:
7 years ago
How to calculate 725*R*1/ 100 and how come 2175?
Please solve it Step By Step.
Please solve it Step By Step.
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?
Shibat said:
7 years ago
@S Padma.
Principle=725 r=r% at the beginning of the year so t =1year.
After the 8 months sum of rupees, 362.50 is given additional so the total principle is; P=725+362.50=1087.50,
t =(12-8)=4 months i.e 4/12 so t=1/3 r=2r.
Rate =(725 * r * 1)/100 + ( 1087.50 * 2r * 1)/100*3 = 33.50.
=> 725*3r +2175r = 33.50 * 100 *3.
=> 43500 r =10050,
=> r=10050/4350,
=> r=2.31.
Principle=725 r=r% at the beginning of the year so t =1year.
After the 8 months sum of rupees, 362.50 is given additional so the total principle is; P=725+362.50=1087.50,
t =(12-8)=4 months i.e 4/12 so t=1/3 r=2r.
Rate =(725 * r * 1)/100 + ( 1087.50 * 2r * 1)/100*3 = 33.50.
=> 725*3r +2175r = 33.50 * 100 *3.
=> 43500 r =10050,
=> r=10050/4350,
=> r=2.31.
Shibat sunwar said:
7 years ago
The Ans is 2.31.
Second principle is 725+362.5.
Second principle is 725+362.5.
S.Padma said:
7 years ago
Principle=725 r=r% at the beginning of the year so t =1year.
After the 8 months sum of rupees, 362.50 is given additional so the total principle is P=725+362.50=1087.50
t =(12-8)=4 months i.e 4/12 so t=1/3 r=2r.
Rate =(725 * r * 1)/100 + ( 1087.50 * 2r * 1)/100*3 = 33.50
=> 725r +2175r = 33.50 * 100 *3.
=> 2900 r =10050,
=> r=10050/2900,
=> r=3.46%.
After the 8 months sum of rupees, 362.50 is given additional so the total principle is P=725+362.50=1087.50
t =(12-8)=4 months i.e 4/12 so t=1/3 r=2r.
Rate =(725 * r * 1)/100 + ( 1087.50 * 2r * 1)/100*3 = 33.50
=> 725r +2175r = 33.50 * 100 *3.
=> 2900 r =10050,
=> r=10050/2900,
=> r=3.46%.
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