Question

7 The simple interest on a certain sum for 3 1 by 2 at 7% p.a. is rupee 225 more than the simple interest on
the same sum for 4 years at 5% p.a. Find the sum.
​

Answer 1

Step-by-step explanation:

Let the sum be x

case (i)

Principle = x, Rate = 7%, time = 3.5 yrs

Interest = \frac{PTR}{100}

100

PTR

= \frac{x (7)(3.5)}{100}

100

x(7)(3.5)

= \frac{24.5x}{100}

100

24.5x

case (ii)

Principle = x, Rate = 5%, time = 4 yrs

Interest = \frac{PTR}{100}

100

PTR

= \frac{x (5)(4)}{100}

100

x(5)(4)

= \frac{20x}{100}

100

20x

given that, the simple interest for case (i) is Rs 225 more than the simple interest for case (ii)

\frac{24.5x}{100} - \frac{20x}{100} = 225

100

24.5x

−

100

20x

=225

\frac{4.5x}{100}

100

4.5x

= 225

x = \frac{22500}{4.5}

4.5

22500

x = 5000

The sum = Rs 5000