Question

A stationary vendor buys pencils at the rate of 21 pencils for rs 20 and sells them at the rate of 20 pencils for rs 21. his profit percent is about :

Answer 1

Answer:

Step-by-step explanation:

Find the cost price of 1 pencil:

21 pencil = Rs 20

1 pencil = 20 ÷ 21 = Rs 20/21

Find the selling price of 1 pencil:

20 pencils = Rs 21

1 pencil = 21 ÷ 20 = Rs 21/20

Find the profit:

Profit = Selling Price - Cost Price

Profit = 21/20 = 20/21 = Rs 41/420

Find the profit percentage:

Profit Percentage = (profit ÷ Cost Price) x 100

Profit Percentage = (41/420 ÷ 20/21) x 100 = 10.25%

Answer: The profit is 10.25%

Answer 2

Answer:

Profit is 10.25%

Step-by-step explanation:

Given that

Buying price of 21 pencils in rupees = BP = 20

Buying price of 1 pencil in rupees = BP = $\frac{20}{21}$

Also

Selling price of 20 pencils in rupees =SP = 21

Selling price of 1 pencil in rupees = SP = $\frac{21}{20}$

Now, we have to calculate the percentage profit obtained by seller

As we know

$Profit=\frac{SP - BP}{BP}\times100$

$Profit =\frac{\frac{21}{20} - \frac{20}{21}}{\frac{20}{21}}\times100$

$Profit=\frac{\frac{21\times21 - 20\times20}{21\times20}}{\frac{20}{21}}\times100$

$Profit=\frac{441 - 400}{400}\times100$

$Profit=\frac{41 }{400}\times100$

$Profit=10.25 %$

Now, profit is 10.25%