Let:
tc = Time that cindy read
tp = Time that pam read
How much longer did Pam read than Cindy? we need to find the difference, so:
[tex]\begin{gathered} tc=4\frac{3}{4}=\frac{19}{4} \\ tp=7\frac{2}{3}=\frac{23}{3} \\ so\colon \\ d=tp-tc=\frac{23}{3}-\frac{19}{4}=\frac{35}{12}=2\frac{11}{12} \end{gathered}[/tex]