Q. 153.6( 7 Votes )
5 pencils and 7 pens together cost Rs. 195 while 7 pencils and 5 pens together cost Rs. 153.
Find the cost of each one of the pencil and the pen.
Let the cost of pencils be x and cost of pens be y.
The linear equations formed are:
5x + 7y = 195 … (1)
7x + 5y = 153 … (2)
We know that the general form for a pair of linear equations in 2 variables x and y is a1x + b1y + c1 = 0
and a2x + b2y + c2 = 0.
Comparing with above equations,
we have a1 = 5, b1 = 7, c1 = - 195; a2 = 7, b2 = 5, c2 = - 153
We can solve by cross multiplication method using the formula
Substituting values in the formula, we get
⇒ x = 4 and y = 25
The cost of each pencil is Rs.4 and cost of each pen is Rs.25.
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