Question

a sum of money amounts to rs 10000 after 5 years and rs 15000 after 8 years at the same rate of simple interest. find the rate of interest

Answer 1

Answer:

99.99%

Step-by-step explanation:

Given :A sum of money amounts to rs 10000 after 5 years and rs 15000 after 8 years at the same rate of simple interest.

To Find :  find the rate of interest

Solution:

Amount after 5 years = Rs.10000

Amount after 8 years = Rs.15000

So, Simple interest for 3 years = Rs.15000-Rs.10000 =Rs.5000

So, Simple interest in 1 year = $\frac{5000}{3}$

So,  Simple interest in 5 years= $\frac{5000}{3}\times 5$

                                                 = $8333.333$

Amount after 5 years = Rs.10000

Simple interest in 5 years= 8333.333

Principal = Amount - Interest

              =Rs.10000-Rs. 8333.333

              =Rs.1666.667

So, $SI =\frac{P \times R \times T}{100}$

$8333.333 =\frac{1666.667 \times R \times 5}{100}$

$\frac{8333.333 \times 100}{1666.667 \times 5}=R$

$99.99=R$

Hence the rate of interest is 99.99%