Question

From a stationary shop, Archana bought two pencils and three pens for Rs. 40 and Indu bought one pencil and two pens for Rs 25. Find the price of one pencil and one pen graphically.

Answer 1

$Let \: cost \: of \:a \: Pencil = Rs \:x$

$Cost \: of \:a \: Pen = Rs \: y$

/* According to the problem given */

Archana bought two pencils and three pens for Rs. 40

$2x + 3y = 40 \: --(1)$

$i) If \: x = 11 \:then \: y = 6 .$

$ii ) If \: x = 14\:then \: y = 4 .$

plotting the points (11,6) and (14,4) on the graph and joining them we get a straight line .

Indu bought one pencil and two pens for Rs 25.

$x + 2y = 25 \: --(2)$

$iii) If \: x = 5\:then \: y = 10.$

$iv ) If \: x = 15\:then \: y = 5.$

plotting the points (5,10) and (15,5) on the graph and joining them we get a straight line .

From the graph ,

we can find that these two straight lines intersecting at the point ( 5,10) .

Therefore.,

$\red{ Cost \: of \: a \: pencil } \green { = Rs\: 5}$

$\red{ Cost \: of \: a \: pen } \green { = Rs\: 10}$

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