Answer: Marcy used [tex]\dfrac{35}8[/tex] cartons of blueberries for the first batch of pies.
Step-by-step explanation:
Given: Quantities of blueberries = [tex]8\dfrac34[/tex] cartons
[tex]=\dfrac{8\times4+3}{4}=\dfrac{35}{4}[/tex] cartons
Blueberries used for first batch = [tex]\dfrac12[/tex] of (Total)
[tex]=\dfrac12\times\dfrac{35}{4}\\\\=\dfrac{35}{8}[/tex]cartons
Hence, Marcy used [tex]\dfrac{35}8[/tex] cartons of blueberries for the first batch of pies.