Question

The rate of simple interest per annum reduces from 4% to 15/4% and for this, a person's annual income decrease by Rs.60. Determine the principle of that person

Answer 1

let the principle amount be ₹x,

Simple interest at 4% in 1years(let)=

$\frac{p \times r \times t}{100}$

$= > \frac{x \times 4 \times 1}{100}$

$= > \frac{x}{25}$

Amount=S.I.+principle

$= \frac{x}{25} + x$

$= \frac{26x}{25}$

Now,

simple interest at 15/4% in 1years=

$= \frac{x \times 4\times 1}{5\times 100}$

$= > \frac{x}{125}$

Amount=

$\frac{x}{125} + x$

$= \frac{126x}{125}$

According to question,

Amount at 4%-₹60=Amount at 5/4%

$= > \frac{26x}{25} - 60 = \frac{126x}{125}$

$= > \frac{26x - </em></strong><strong><em>1</em></strong><strong><em>500}{25} = \frac{126x}{125}$

multiple both the side by 25 we get:

$= > \frac{26x - </em></strong><strong><em>1</em></strong><strong><em>500}{25} \times 25 = \frac{126x}{125} \times 25$

$= > 26x - </em></strong><strong><em>1</em></strong><strong><em>500 = \frac{126x}{5}$

Cross multiplying:

$= > 130x - </em></strong><strong><em>7</em></strong><strong><em>500 = 126x$

Transposing:

$= > 130 x - 126x = </em></strong><strong><em>7</em></strong><strong><em>500$

$= > 4x = </em></strong><strong><em>7</em></strong><strong><em>500$

$= > x = \frac{</em></strong><strong><em>7</em></strong><strong><em>500}{4}$

$= > x = </em></strong><strong><em>1</em></strong><strong><em>8</em></strong><strong><em>7</em></strong><strong><em>5</em></strong><strong><em>rupes$

Principle=₹1875

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Answer 2

Answer:

Step-by-step explanation: