Question

a sum of money amounts to 10000 after 5 years and 15000 after 8 years at same rate of interest. Find the rate of interest p. a ? ​

Answer 1

Answer:

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}35000

So,  Simple interest in 5 years= \frac{5000}{3}\times 535000×5

                                                = 8333.3338333.333

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}SI=100P×R×T

8333.333 =\frac{1666.667 \times R \times 5}{100}8333.333=1001666.667×R×5

\frac{8333.333 \times 100}{1666.667 \times 5}=R1666.667×58333.333×100=R

99.99=R99.99=R

Hence the rate of interest is 99.99%