Question

(i) In how many years will Rs. 950 produce Rs. 399 as simple interest at 7%?
(ii) Find the time in which Rs. 1200 will amount to Rs. 1536 at 3.5% per year?

Answer 1

(i) P= Rs. 950
S.I.=Rs. 399
R=7%
We know that
$T=\frac{100\times 1}{P\times R}=\frac{100\times 399}{950\times 7}$
$=\frac{100\times 21}{5\times 7}=2\times 3=6$years
(ii) A= Rs. 1536
P= Rs. 1200
I=A-P
=Rs. 1536-Rs.1200
=Rs. 336
We know that:
$T=\frac{100\times I}{P\times R}$
$=\frac{100\times 336}{1200\times 3.5}=\frac{100\times 336\times 10}{1200\times 35}[\because \frac{1}{3.5}=\frac{10}{35}]$
$=\frac{28\times 10}{35}=8years$