This is the basic and conceptual question from linear equations in two variables in which we have been asked to calculate the value of 1 pen and 1 pencil if it is given that the cost of 5 pens and 8 pencils is ₹120 and it is also given that the cost of 8 pens and 5 pencils is 153.
Kindly solve the above problem by using the properties of linear equations
RS Aggarwal, Class 10, chapter 3F, question no 8
Let the cost of one pen is Rs.x and cost of one pencil is Rs.y, then
As per statement
5x+8y=120...(1)
8x+5y=153...(2)
Adding both the equations, we get
13x+13y=273
x+y=21....(3)
On subtracting (1) from (2),
3x−3y=33
x−y=11...(iv)
Again
Adding (3) and (iv).
2x=32 or x=16
On subtracting
2y=10 or y=5
Answer:
Cost of pen =Rs.16
and cost of pencil =Rs.5