George and Wesley shared some pens in the ratio of 3 : 8. After both each gave away 20 pens to their brother, the ratio of the number of pens George had to the total number of pens left was 1 : 5. How many pens did the two boys have at first?

	George	Wesley	Difference
Before	3x3 = 9 u	8x3 = 24 u	5x3 = 15 u
Change	- 20	- 20
After	1x5 = 5 u	4x5 = 20 u	3x5 = 15 u

Number of pens that George and Wesley each gave to their brother is the same.

The difference in the number of pens at first and in the end between George and Wesley remains unchanged.  Make the difference in the number of pens the same.  LCM of 5 and 3 is 15.

Number of pens that George gave to their brother
= 9 u - 5 u
= 4 u

4 u = 20

1 u = 20 ÷ 4 = 5

Number of pens that the two boys had at first
= 9 u + 24 u
= 33 u
= 33 x 5
= 165

Answer(s): 165