Question

A shopkeeper bought pens at the rate of 8 pens for Rs. 34 and sold them at 12 pens for 57. The number of pens, that he should sell to have a profit of Rs. 900 must be?

Answer 1

Answer:

$number \: of \: pens \: should \:he \:sell \\to \: get \: a \: profit \: of \: Rs\: 900 = 1800$

Step-by-step explanation:

$cost \:price \:of \: 8 \:pens= Rs \: 34$

$cost \:price \:of \: 1 \:pen= \frac{Rs \: 34}{8} \\= \frac{17}{4} \:--(1)$

$selling \:price \:of \: 12 \:pens= Rs \: 57$

$selling \:price \:of \: 1 \:pen= \frac{Rs \: 57}{12} \\= \frac{19}{4} \:--(2)$

$\blue { profit }$

$= selling \:price - cost \:price$

$= \frac{19}{4} - \frac{17}{4} \\= \frac{19-17}{4}\\= \frac{2}{4} = \frac{1}{2}$

$Let \: number \: of \: pens \: should \:he \:sell \\to \: get \: a \: profit \: of \: Rs\: 900 = n$

$n \times \frac{1}{2} = 900$

$\implies n = 900 \times 2 = 1800$

Therefore.,

$number \: of \: pens \: should \:he \:sell \\to \: get \: a \: profit \: of \: Rs\: 900 = 1800$

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