Answer:
24 minutes
Step-by-step explanation:
Fred can mow a lawn in 60 minutes.
Fred's Rate [tex]=\frac{1}{60}[/tex]
Rocky can mow the same lawn in 40 minutes.
Rocky's rate [tex]=\frac{1}{40}[/tex]
Let the time it will take both of them = x minutes
Therefore:
[tex]\frac{1}{60}+\frac{1}{40}=\frac{1}{x}\\$Multiply all through by 1200$\\1200\times \frac{1}{60}+1200\times\frac{1}{40}=1200\times\frac{1}{x}\\20+30=\frac{1200}{x}\\50=\frac{1200}{x}\\$Cross multiply\\50x=1200\\Divide both sides by 50\\x=24\\[/tex]
It would take the two of them 24 minutes to mow the lawn.
