#### Answer

4

#### Work Step by Step

7$\frac{3}{5}$ hours to 1$\frac{9}{10}$ hours
$\frac{7\times5 +3}{5}$ to $\frac{1\times10 +9}{10}$
= $\frac{35 +3}{5}$ to $\frac{10 +9}{10}$
= $\frac{38}{5}$ to $\frac{19}{10}$
= $\frac{38}{5}$ $\div$ $\frac{19}{10}$
= $\frac{38}{5}$ $\times$ $\frac{10}{19}$
= $\frac{38\times10}{5\times19}$
= $\frac{19\times2\times5\times2}{5\times19}$
=$\frac{2\times2}{1}$
=$\frac{4}{1}$
=4