Answer:
b. 2.4 hours
Step-by-step explanation:
Since, William completes in 4 hrs and Stephanie in six hrs.
[tex]William's\: 1 \: hours \: job = \frac{1}{4} \\ Stephanie's \: 1 \: hours \: job = \frac{1}{6} \\ 1 \: hours \: work \: of \: both \: together \\ = \frac{1}{4} + \frac{1}{6} = \frac{6 + 4}{24} = \frac{10}{24} \\ total \: time \: taken \: to \: complete \: the \: job \\ = \frac{24}{10} \\ = 2.4 \: hours[/tex]
