Answer:
![t = 96 minutes](https://img.qammunity.org/2020/formulas/physics/high-school/cih8ht9a9jw6vjtgm4qv210cayuvl72s2c.png)
Step-by-step explanation:
Time to mow 1 lawn by Wilma is 80 minutes
so work done in 1 minute by Wilma is given as
Similarly Rocky mow same lawn in 120 minute
so work done in 1 minute by Rocky is given as
![W_2 = (1)/(120)](https://img.qammunity.org/2020/formulas/physics/high-school/jiscy2hx9s9bv6nf6khcilk9h3jh6a48vz.png)
now we know that they both worked by "t" time
so total work performed by them
![W = (t)/(80) + (t)/(120)](https://img.qammunity.org/2020/formulas/physics/high-school/mxubbxwvpc094mp1rcuxhgcqx2bz2txidh.png)
they both mow 2 lawns then it is given as
![2 = ((1)/(80) + (1)/(120))t](https://img.qammunity.org/2020/formulas/physics/high-school/kvvoggzeoeiyuf1tcxmz6nctmyh5e2me2j.png)
![t = 96 minutes](https://img.qammunity.org/2020/formulas/physics/high-school/cih8ht9a9jw6vjtgm4qv210cayuvl72s2c.png)