Question

In how much time will * 10000 yield an interest
of8500 at the rate of 8.5%? Within the same
time period, at what rate of interest will the
sum double itself?​

Answer 1

Time = 10 years, Rate = 17%

Step-by-step explanation:

To calculate the time for a certain amount to produce a fixed interest we use the formula;

$Simple\ Interest = \frac{Principal\ *\ Rate\ *\ Time}{100}$

Given:

Principal = Rs. 10,000

Interest = Rs. 8500

Rate = 8.5%

Substituting:

$8500 = \frac{10000\ *\ 8.5\ *\ Time}{100}$

$Time = \frac{8500 * 100}{10000 * 8.5}$

Time = 10 years.

The rate at which the interest will double;

Substituting:

$8500 * 2 = \frac{10000\ *\ Rate\ *\ 10}{100}$

$Rate = \frac{8500 * 2 * 100}{10000 * 10}$

Rate  = 17%