Shiyun and Victoria have some puffs each. If Shiyun gives Victoria 10 puffs, Shiyun will have ⁴₅ as many puffs as Victoria. If Shiyun gives Victoria 5 puffs, they will have an equal number of puffs. How many puffs does Shiyun have at first?

	Case 1		Case 2
	Shiyun	Victoria	Shiyun	Victoria
Before	4 u + 10	5 u - 10	4.5 u + 5	4.5 u - 5
Change	- 10	+ 10	- 5	+ 5
After	4 u	5 u	4.5 u	4.5 u

Total number of puffs that Shiyun and Victoria have
= 4 u + 5 u
= 9 u 

Number of puffs that Shiyun and Victoria each has in the end is the same.

Number of puffs that Shiyun and Victoria each has in the end in Case 2
= 9 u ÷ 2
= 4.5 u

Number of puffs that Shiyun had at first is the same in Case 1 and Case 2.

4.5 u + 5 = 4 u + 10
4.5 u - 4 u = 10 - 5
0.5 u = 5

1 u = 5 ÷ 0.5 = 10

Number of puffs that Shiyun has
= 4 u + 10
= 4 x 10 + 10
= 40 + 10
= 50

Answer(s): 50