Question 971747
The rates are in units of square feet per hour.
Let r be the rate for 1 man.


RT=A  for rate time area.


{{{5r*4=60^2}}}, the first sentence.


unknown number of hours t:
{{{10r*t=180^2}}}, the question, second sentence.



This is a Uniform Rates problem, and does not involve any quadratic equation.  The second equation, although contains a term of {{{rt}}}, is still not quadratic.


Be sure you study the discussion given and understand it.  Once done, the first equation lets you solve for r, and then substitute for r in the second equation, and solve that one for t.