Answer:
[tex]t = 96 minutes[/tex]
Explanation:
Time to mow 1 lawn by Wilma is 80 minutes
so work done in 1 minute by Wilma is given as
[tex]W_1 = \frac{1}{80}[/tex]
Similarly Rocky mow same lawn in 120 minute
so work done in 1 minute by Rocky is given as
[tex]W_2 = \frac{1}{120}[/tex]
now we know that they both worked by "t" time
so total work performed by them
[tex]W = \frac{t}{80} + \frac{t}{120}[/tex]
they both mow 2 lawns then it is given as
[tex]2 = (\frac{1}{80} + \frac{1}{120})t[/tex]
[tex]t = 96 minutes[/tex]