A borrowed Rs. 2500 at a certain rate of simple interest and Rs. 1500 at 3% higher rate of interest. If after 4 years the interest paid by him in both cases is Rs. 1140, the former rate of interest was:

It is clear that if the same amount of Rs. 100 is paid at the end of 2nd, 3rd and 4th years also then the amount so settled will be Rs. 100 + Rs. 105 + Rs. 110

+ Rs. 115 = Rs. 430

Therefore, to clear the debt of Rs. 430 annual instalment

= Rs. 100

:.To clear the debt of Rs. 645, annual instalment = (100 x 435)/645 = Rs.150

So, Annual instalment will be Rs.150

6.

A sum of Rs. 1850 lent out for 5 years at 3% p.a . simple interest will amount to :

P = Rs.892, R = 6% and time = 8months or 8/12 = 2/3 year

SI = (892 x 6 x 2/3)/100 = Rs.35.68

P = (SI x 100)/(R x T) = (81 x 100)/(6 x 4(1/2)) = (81 x 100 x 2)/(6 x 4) = Rs.300

10.

A sum of money amounts to Rs. 1150 in 3 year s and to Rs. 1250 in 5 years at a certain rate per cent p.a. simple interest. The rate per cent p.a.will be :