Answer :
1/2*6 = 3. It will take him 3 hours to finish his test if he continues on the same rate
[tex]1-\frac{1}{6}=\frac{5}{6}\\\\\begin{array}{ccc}\frac{1}{6}\ of\ the\ test&-&\frac{1}{2}\ h\\\\\frac{5}{6}\ of\ the\ test&-&x\ h\end{array}\ \ \ \ |cross\ multiply\\\\\\\frac{1}{6}x=\frac{1}{2}\cdot\frac{5}{6}\\\\\frac{1}{6}x=\frac{5}{12}\ \ \ \ \ |multiply\ both\ sides\ by\ 6\\\\\boxed{x=\frac{5}{2}=2.5\ (h)}\leftarrow time\ he\ will\ have\ to\ do\ the\ test\\\\\\total\ test\ time:2.5\ h+0.5\ h=3\ h[/tex]
