Question

A sum of money at si amounts to rs.9440 in 3 years.if the rate of interest is increased

Answer 1

Solution :-

The above question is incomplete. I have solved a similar question like this. Question should be like this.

A sum of money at simple interest amounts to Rs. 9440 in 3 years. If the rate of interest is increased by 25 %, the same sum of money amounts to Rs. 9800 in the same time. Find the rate of interest.

According to the question.

Simple Interest = (P*R*T)/100

⇒ (P*R*3)/100 = 9440 - P .....................(1)

⇒ (P*5/4R*3)/100 = 9800 - P ................(2)

Now, subtracting equation (1) from (2)

⇒ 15PR/400 - 3PR/100 = 9800 - P - 9440 + P

⇒ (15PR - 12PR)/400 = 360

⇒ 3PR/400 = 360

⇒ 3PR = 400*360

⇒ 3PR = 144000

⇒ PR = 144000/3

⇒ PR = 48000

Substituting the value of PR = 48000 in equation (1)

⇒ (48000*3)/100 = 9440 - P

⇒ 144000/100 = 9440 - P

⇒ 1440 = 9440 - P

⇒ P = 9440 - 1440

⇒ P = 8000

Substituting the value of P = 8000 in (1)

⇒ (8000*R*3)/100 = 9440 - 8000

⇒ 24000R/100 = 1440

⇒ 24000R = 1440*100

⇒ 24000R = 144000

⇒ R = 144000/24000

⇒ R = 6

So, the rate of interest is 6 %

Answer.