Question

A shopkeeper buys a number of pens for Rs. 600. If he had bought 10 dozen more pens for the same amount, each dozen would have cost him Rs. 2 less. Find the number of pens bought by him.

Answer 1

Answer:

$let \: x \: dozen \: of \: bananas \: are \: bought \: by \: the \: shopkeeper.$

$cost \: of \: x \: bananas = 600$

$cost \: of \: 1 \: banana = \frac{600}{x}$

$according \: to \: the \: given \: information \:$

$we \: have$

$= > \frac{600}{x} - \frac{600}{10 + x} = 2$

$simplifying$

$we \: get$

$= > {x}^{2} + 10x - 3000 = 0$

$= > (x - 50)(x - + 60) = 0$

$= > 50 \: or \: - 60$

$neglecting \: the \: negative \: value \:$

$we \: get \: x = 60$

$thus \: 50 \: dozens \: of \: bananas \: were \: bought \: by \: the \: shopkeeper.$