Aptitude - Simple Interest - Discussion

No @Bhuvana,

Its not working for all, its depend upon the problem all are our mind calculation.

@Mathan.

Whether this formula works in all those similar problems?

In first step >>> S.I. for 3 years = Rs. (12005 - 9800) = Rs. 2205.

How come it is S.I = 2205?. It should be difference in SI + Principal for 3 years = 2205. How come it is SI alone?

12005 is SI + Principal for 5yrs and 9800 is also SI + Prncpl for 8 yrs.

please someone explain?

Thanks madhan, I understand it, thanks lot.

Amount = P+I for 5 years = 9800 --- Eq(1).

Amount = P+I for 8 years =12005 -- Eq(2).

Eq(2)-Eq(1) => Amount = 735 for 3yrs.

Amount = P+I per year = 2205/3 = 735.

Therefore data is Inadequate to find Rate of interest.

But why Everyone took 9800 as SI sometimes and as principal sometimes. please help

Why s.i for 3yrs and 5yrs are taken instead of 5yrs and 8yrs?

@Insaan

Actually the question is wrong because it is simple interest while it should be amount. And your solution is correct if it would have been amount.

@ Akhi - the answer of your question is 8%.. its done like the above question here..see

S.I for 3 years (5-2) = 120
S.I for 1 year = 120/3 = 40
hence, S.I for 2 years is 2*40 = 80. (you can also calculate for 5 years instead of 2 years)
Principal = Amount - SI
580 - 80 [amount can also be 700 if we take 5 years]
500
Now, we know SI aswell as Principal
therefore using formula
S.I = PRT/100
80 = 500*R*2/100 [ T can also b 5 if we consider 5 years]
R = 8

Ques: The simple interest of a certain sum for 2 years is Rs 580 and for 5 years is Rs 700 with the same rate of interest. Find the rate of interest.

Can anyone solve this please?

Hai Asd,

In the question we can find "The sum of amount 9800 " it means, principal + SI=9800. So p=9800-SI of 5 years.

I hope u got it.