a)
We know that Kevin spent $3 for 6 pounds of sugar, this means that he can get:
[tex]\frac{6}{3}=2[/tex]Therefore, he can get 2 pounds of sugar per dollar.
b)
If we divide the cost given by the time we have that:
[tex]\frac{37}{7}=5.29[/tex]Hence, it means that an hour cost $5.29. Now, if we want to know the how much time we get for a dollar we use a rule of three:
[tex]\begin{gathered} 5.29\rightarrow1 \\ 1\rightarrow x \end{gathered}[/tex]then:
[tex]\begin{gathered} x=\frac{1\cdot1}{5.29} \\ x=0.19 \end{gathered}[/tex]Therefore, we get 0.19 hours per dollar (this is approximately 11 minutes)