As we are comparing the time it took Chris to clean the bathroom and the kitchen, we need to subtract the time that Chris took to clean the kitchen from the time he took to clean the bathroom, as shown below.
[tex]3\frac{4}{5}_{}-2\frac{1}{2}=\frac{15+4}{5}-\frac{4+1}{2}=\frac{19}{5}-\frac{5}{2}[/tex]Then,
[tex]\begin{gathered} \Rightarrow3\frac{4}{5}_{}-2\frac{1}{2}=\frac{2\cdot19-5\cdot5}{5\cdot2}=\frac{38-25}{10}=\frac{13}{10} \\ \Rightarrow3\frac{4}{5}_{}-2\frac{1}{2}=\frac{10}{10}+\frac{3}{10}=1+\frac{3}{10}=1\frac{3}{10} \\ \Rightarrow3\frac{4}{5}_{}-2\frac{1}{2}=1\frac{3}{10} \end{gathered}[/tex]The answer is 1 3/10 hours
