Zoe and Xylia have some shortbreads each. If Zoe gives Xylia 25 shortbreads, Zoe will have ²₅ as many shortbreads as Xylia. If Zoe gives Xylia 4 shortbreads, they will have an equal number of shortbreads. How many shortbreads does Xylia have at first?

	Case 1		Case 2
	Zoe	Xylia	Zoe	Xylia
Before	2 u + 25	5 u - 25	3.5 u + 4	3.5 u - 4
Change	- 25	+ 25	- 4	+ 4
After	2 u	5 u	3.5 u	3.5 u

Total number of shortbreads that Zoe and Xylia have
= 2 u + 5 u
= 7 u 

Number of shortbreads that Zoe and Xylia each has in the end is the same.

Number of shortbreads that Zoe and Xylia each has in the end in Case 2
= 7 u ÷ 2
= 3.5 u

Number of shortbreads that Zoe had at first is the same in Case 1 and Case 2.

3.5 u + 4 = 2 u + 25
3.5 u - 2 u = 25 - 4
0.5 u = 21

1 u = 21 ÷ 0.5 = 42

Number of shortbreads that Xylia has
= 5 u - 25
= 5 x 42 - 25
= 210 - 25
= 185

Answer(s): 185