Question

The cost price 13 books is equals to the selling price of 10 books. Find the profit percent.​

Answer 1

Answer:

Let the cost price of one book be Rs.x

Cost price of 13 books be 13x

And the selling price of one book be Rs.y

Selling price of 10 books be 10y

According to condition:

10y=13x

$⇒y = \frac{13}{10}x$

Profit is given by S.P-C.P= y-x

$⇒ \frac{13}{10}x - x \\ \\ ⇒\frac{13x - 10x}{10} \\ \\ ⇒ \frac{2x}{10}$

Profit percentage=

$⇒ \frac{ \frac{2x}{10} }{x} \times 100$

$⇒ \frac{2}{10} \times 100$

$⇒2 \times 10$

$⇒20\%$

Therefore, The profit percentage is 20%

Answer 2

Let the cost price of one book be Rs.x

Cost price of 13 books be 13x

And the selling price of one book be Rs.y

Selling price of 10 books be 10y

According to condition:

10y=13x

⇒y = \frac{13}{10}x⇒y=

10

13

x

Profit is given by S.P-C.P= y-x

\begin{gathered}⇒ \frac{13}{10}x - x \\ \\ ⇒\frac{13x - 10x}{10} \\ \\ ⇒ \frac{2x}{10} \end{gathered}

⇒

10

13

x−x

⇒

10

13x−10x

⇒

10

2x

Profit percentage=

⇒ \frac{ \frac{2x}{10} }{x} \times 100⇒

x

10

2x

×100

⇒ \frac{2}{10} \times 100⇒

10

2

×100

⇒2 \times 10⇒2×10

⇒20\%⇒20%

Therefore, The profit percentage is 20%