Tammy and Eva have some biscuits each. If Tammy gives Eva 18 biscuits, Tammy will have ³₄ as many biscuits as Eva. If Tammy gives Eva 7 biscuits, they will have an equal number of biscuits. How many biscuits does Eva have at first?

	Case 1		Case 2
	Tammy	Eva	Tammy	Eva
Before	3 u + 18	4 u - 18	3.5 u + 7	3.5 u - 7
Change	- 18	+ 18	- 7	+ 7
After	3 u	4 u	3.5 u	3.5 u

Total number of biscuits that Tammy and Eva have
= 3 u + 4 u
= 7 u 

Number of biscuits that Tammy and Eva each has in the end is the same.

Number of biscuits that Tammy and Eva each has in the end in Case 2
= 7 u ÷ 2
= 3.5 u

Number of biscuits that Tammy had at first is the same in Case 1 and Case 2.

3.5 u + 7 = 3 u + 18
3.5 u - 3 u = 18 - 7
0.5 u = 11

1 u = 11 ÷ 0.5 = 22

Number of biscuits that Eva has
= 4 u - 18
= 4 x 22 - 18
= 88 - 18
= 70

Answer(s): 70