Answer:
[tex]8\dfrac{3}{4}[/tex] galloons of coffee had been dispensed.
Step-by-step explanation:
Quantity of coffee in starting [tex]=9\dfrac{7}{8}=\dfrac{79}{8}[/tex] galloons
Left coffee [tex]=1\dfrac{1}{8}=\dfrac{9}{8}[/tex]
Dispensed coffee,
[tex]=\dfrac{79}{8}-\dfrac{9}{8}\\\\=\dfrac{79-9}{8}\\\\=\dfrac{70}{8}\\\\=\dfrac{35}{4}\\\\=8\dfrac{3}{4}[/tex]
Hence, [tex]8\dfrac{3}{4}[/tex] galloons of coffee had been dispensed.