Step-by-step explanation:
Since, Carlos completes the work in 5 hours.
So, in one hour she will do [tex] =\frac{1}{5}[/tex] part
Since, Jenny completes the work in 9 hours.
So, in one hour she will do [tex] =\frac{1}{9}[/tex] part
(Carlos + Jenny)'s one hour work together
[tex] =\frac{1}{5}+\frac{1}{9}\\
= \frac{9+5}{5\times 9}\\
= \frac{14}{45}\\[/tex]
Total time taken by Carlos and Jenny together [tex] =\frac{45}{14}= 3\frac{3}{14} \: hours[/tex]
