Question

30. On a sum of money at 8% simple rate of
interest per annum, the difference of
simple interests of 5 years and 8 years is
Rs.120. What is the principal?​

Answer 1

Step-by-step explanation:

Given :-

On a sum of money at 8% simple rate of

interest per annum, the difference of

simple interests of 5 years and 8 years is Rs.120.

To find:-

What is the principal?

Solution :-

Let the principle be Rs. X

Rate of Interest = 8%

Time = 5 years

We know that

Simple Interest = PTR/100

=> (X×5×8)/100

=> 40X/100

=> 2X/5

Simple Interest for 5 years = Rs. 2X/5 -------(1)

Rate of Interest = 8%

Time = 8 years

We know that

Simple Interest = PTR/100

=> (X×8×8)/100

=> 64X/100

=> 16X/25

Simple Interest for 8 years = Rs. 16X/25 ------(2)

Given that

The difference of simple interests of 5 years and 8 years = Rs.120.

=> (16X/25)-(2X/5) = 120

=> (16X-10X)/25 = 120

=> 6X/25 = 120

=> 6X = 120×25

=> X = 120×25/6

=>X = 20×25

=>X = 500

Therefore, X = Rs. 500

Answer:-

Principle for the given problem is Rs. 500

Used formulae:-

• Simple Interest = PTR/100
• P = Principle
• T = Time
• R = Rate of Interest