**(i) At what rate per cent per annum will Rs. 630 produce an interest of Rs.126 in 4 years? (ii) At … year will a sum double itself in…**

###### Answers:

(i) P = Rs. 630,

I = Rs. 126

T = 4 Years

R = (100 × I)/(P × T) = (100 × 126)/(630 × 4) = 100/20 = 5%

(ii) Let P = Rs. 100

∴ Amount = 2 × Rs. 100 = Rs. 200

Interest = A – P

= Rs. 200 – Rs. 100 = Rs. 100

T = 6. ¼ years = 25/4 years

R = (100 × I)/(P × T) = ((100 × 100)/100 × 25/4)% = ((100 × 100)/100 ) × (4/25) = 16%