Question

5 pencils and 7 pens together cost 350 whereas 7 pencils and 5 pens together cost 46.
Find the cost of one pencil and that of one pen.
Half the perimeter of a rectangular garden, whose length is 4m more than its width, is 36m.​

Answer 1

Let pencil be x and let pen be y

5x+7y=50

7x+5y=46

Multiply the first equation by 7

35x+49y=350

Multiply the second equation by 5

35x+25y=230

solving them we get 24y=120 which gives y is 5 rupees

substituting in the second equation we get x is 3 rupees