Aptitude - Simple Interest - Discussion

Discussion Forum : Simple Interest - General Questions (Q.No. 12)
12.
What will be the ratio of simple interest earned by certain amount at the same rate of interest for 6 years and that for 9 years?
1 : 3
1 : 4
2 : 3
Data inadequate
None of these
Answer: Option
Explanation:

Let the principal be P and rate of interest be R%.

Required ratio =
P x R x 6
100
= 6PR = 6 = 2 : 3.
P x R x 9
100
9PR 9

Video Explanation: https://youtu.be/GaaEDwTWc6w

Discussion:
16 comments Page 1 of 2.

Anchal said:   1 decade ago
Dear Insaan and Angle, we know we got same Ans from your's method. But there is no any logic. Thats why we have to needed the interest formula. And through the interest formula we can also find out ratio even in different rate of interest.

Ashik said:   1 decade ago
Assume the amount=100

If interest is 10% ,amount of interest is 10 rs.

then the amount of interest for 6 yrs = 6*10 rs = 60 rs

and for 9 yrs amt of interest for 9 years = 9*10 rs = 90rs

For ratio, s1/s2 = 60/90 = 2/3.

Indramani said:   8 years ago
Answer should be data inadequate. Suppose principal is 100 and we take 5% interest, then after 6yrs it will be 130 and after 9 years it will be 145. Solving this gives 26/29 which is not equal to 2/3.

Anomy said:   4 years ago
@Amrik Singh,

The Rate of interest and principal are constant. As time lies, in the numerator of the formula. The interests will be directly proportional to time.
(1)

Karthik said:   4 years ago
Easy way;

Just assume 100 as principle 10 %percetage interest.
So 6years it becomes 160 interest is 60,
9 years it becomes 190 interest 90.
60:90 = 2:3.
(1)

Kyomuhendo Marvin said:   2 years ago
We Know,

SI = [(P*R*T)/100].
Lets Assume P = 100, R = 3%.

Therefore,
SI = [(100*3*6)/100) : [(100*3*9)/100].
= 18 : 27.
= 18/27.
= 2:3.
(1)

Riya said:   3 months ago
When the principal and rate of interest are constant, then Simple interest is directly proportional to time.

So, here the answer is 2:3.

Angle said:   1 decade ago
Lets interest of certain amount is X.

so after 6 year is 6X and after 9 year is 9X.

For Ratio ==> 6X : 9X = 2:3

Insaan said:   1 decade ago
Simple way is

S.I is directly proportional to T, we can write

S1/S2 = T1/T2
= 2/3

Amrik singh said:   6 years ago
3:2 is correct. Not 2:3 because rate of interest is inversly proportional to time.


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