Aptitude - Simple Interest - Discussion

(2205/3) * 5 ?

@Xyz

For calculationg SI for 1 year we divide it by 3 first and then we want 5yr SI, so we multiplied it by 5 got it.

Principal = Rs. (9800 - 3675) = Rs. 6125 ?

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.

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?

@ 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

@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.

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

For this type of Question, use this formula.

a = 9800 ; b = 12005 ; t1 = 5 yrs ; t2 = 8 yrs

Principal = (at2 - bt1)/(t2-t1)

Rate = ((b-a)x100)/(bt1-at2) %

Hope it works.

Thanks madhan, I understand it, thanks lot.