Gillian, Kylie and Roshel had a total of 145 erasers. The ratio of Kylie's erasers to Roshel's erasers was at first 6 : 7. After Gillian and Kylie each gave half of their erasers away, the 3 children had 104 erasers left. How many erasers did Gillian and Kylie have at first?

	Gillian	Kylie	Roshel	Total
Before	2 p	6 u	7 u	145
Change	- 1 p	- 3 u		- 41
After	1 p	3 u	7 u	104

Number of erasers that Gillian and Kylie gave away
= 145 - 104
= 41

1 p + 3 u = 41
1 p = 41 - 3 u --- (1)

1 p + 3 u + 7 u = 104
1 p + 10 u = 104
1 p = 104 - 10 u --- (2)

(1) = (2)
41 - 3 u = 104 - 10 u
10 u - 3 u = 104 - 41
7 u = 63

1 u = 63 ÷ 7 = 9

From (1)
1 p = 41 - 3 u
1 p = 41 - 3 x 9

1 p = 41 - 27 = 14

Number of erasers that Gillian and Kylie had at first
= 2 p + 6 u
= 2 x 14 + 6 x 9
= 28 + 63
= 91

Answer(s): 91