Question

Riya has pens and pencils, which together are 40 in number. If she had 5 more pencils and 5 less pens, then the number of pencils would become four times the number of pens. Find the original number of pens and pencils.

Answer 1

Pens=13

Pencils=27

Explanation:

1. Pens = x, Pencils = y

x+y=40

2. y+5 & x-5 --> y=4x

3. Rearrange the x+y=40 to y=40-x. Then substitute y=4x and y=40-x to 4x=40-x.

4. Solve. 4x=40-x, 5x=40, x=8

5. Plug in x=8 to y=4x -> y=32.

6. Reverse the y+5 & x-5. y=27, x=13.