Ahmad and Gabriel have some blue pens and some yellow pens. The number of yellow pens Ahmad has is equal to the number of blue pens Gabriel has. ¹₅ of Ahmad's pens are blue and ⁴₅ of Gabriel's pens are yellow. There are a total of 60 blue pens. Find the total number of pens they have.

Ahmad		Gabriel		Total
Blue	Yellow	Blue	Yellow
	1x4	1x4
1x1	4x1	1x4	4x4
1 u	4 u	4 u	16 u	25 u

The number of Ahmad's yellow pens and Gabriel's blue pens is the same.

The number of Ahmad's yellow pens is repeated. The number of Gabriel's blue pens is repeated.  Make the number of Ahmad's yellow pens and Gabriel's blue pens the same.  LCM of 4 and 5 is 4.

Number of blue pens
= 1 u + 4 u
= 5 u

5 u = 60

1 u = 60 ÷ 5 = 12

Total number of pens
= 1 u + 4 u + 4 u + 16 u
= 25 u
= 25 x 12
= 300

Answer(s): 300