We have to divide 2 1/4 by 3 to get the number of cups the baker should use. Then we have the following:
[tex]\begin{gathered} 2\frac{1}{4}=\frac{9}{4} \\ \Rightarrow\frac{\frac{9}{4}}{3}=\frac{9}{4\cdot3}=\frac{3}{4}=0.75 \end{gathered}[/tex]therefore, the baker should put 0.75 cups of blueberries in each batch