It is given that ,
[tex]\frac{4\text{ hr}}{5.6\text{ hr}}[/tex]Write the ratio as whole numbers,
[tex]\frac{40\text{hr}}{56\text{ hr}}[/tex]Reduce the fraction to its simplest form,
[tex]\frac{5}{7}[/tex]Therefore the given ratio in simplest form is written as,
[tex]\frac{5}{7}[/tex]