Question

The difference between simple interest on a sum of money for 5 years and for 3 years at 5 % per annum is Rs. 600 Find the sum. for class 7 th studentl also solve the questions in the image​

Answer 1

For ,

N=3years

R=5 %

We have S.I.=

100

PNR

​

=Rs600

=>

100

P×3×5

​

=600

=>P=Rs4,000

And on interest being compounded for 2 years, Amount=P(1+

100

R

​

)

N

=4,000×(1+

100

5

​

)

3

=4,000×1.05

3

=Rs4,630.50

So, C.I.=A−P=Rs4,630.50=Rs4,000=Rs630

Answer 2

Answer -

1)

For first simple interest,

Time = 5 years

Rate of interest = 5%

SI =

$\frac{P \times R \times T}{100} \\ = \frac{P \times 5 \times 5}{100} \\ = \frac{P}{4}$

For second simple interest,

Time = 3 years

Rate of Interest = 5%

SI =

$\frac{P \times R \times T}{100} \\ = \frac{P \times 3 \times 5}{100} \\ = \frac{3P}{20}$

Their difference = Rs 600

According to condition :-

$\frac{P}{4} - \frac{3P}{20} = 600 \\ = \frac{5P - 3P}{20} = 600 \\ = \frac{2P}{20} = 600 \\ = 2P = 600 \times 20 \\ = 2P = 12000 \\ = P = \frac{12000}{2} \\ = P = 6000$

The sum is Rs 6000

Hence the Principal is Rs 6000.