Q1. Form the pair of linear equations in the following problems, and find their solutions graphically.
(ii) 5 pencils and 7 pens together cost Rs 50, whereas 7 pencils and 5 pens together cost Rs 46. Find the cost of one pencil and that of one pen.
Let x be the price of 1 pencil and y be the price of 1 pen,
Now, According to the question
And
Now, The points (x,y), that satisfies the equation (1) are
X | 3 | -4 | 10 |
Y | 5 | 10 | 0 |
And, The points(x,y) that satisfies the equation (2) are
X | 3 | 8 | -2 |
Y | 5 | -2 | 12 |
The Graph,
As we can see from the Graph, both line intersects at point (3,5) that is, x = 3 and y = 5 which means cost of 1 pencil is 3 and cost of 1 pen is 5.