Question

I have a pouch with pens and pencils in it. at the moment, the ratio of pens to pencils is 3:5. if phil gives me 3 pens in exchange for 9 of my pencils, i will have an equal number of pens and pencils. how many pens will that be?

Answer 1

Ratio of pens : pencils = 3 : 5

Let x be the number of parts

3x + 3 = 5x - 9

2x = 12

x = 6

Total pens before exchange = 6 x 3 = 18

Total pens after exchange = 18 + 3 = 21

Answer: 21 pens