Answer: Number of hours they all will take is [tex]\frac{12}{7}=1\frac{5}{7}\ hours[/tex]
Step-by-step explanation:
Since we have given that
Number of hours Walter and Bill takes to do the job = 4 hours
Number of hours Tom alone takes to do the job = 3 hours
We need to find the number of hours takes them together to decorate the room.
Work done by Walter and Bill = [tex]\frac{1}{4}[/tex]
Work done by Tome = [tex]\frac{1}{3}[/tex]
total work done by three is given by
[tex]\frac{1}{4}+\frac{1}{3}\\\\=\frac{3+4}{12}\\\\=\frac{7}{12}[/tex]
Hence, Number of hours they all will take is [tex]\frac{12}{7}=1\frac{5}{7}\ hours[/tex]
