Question 879900
Unsure if you want this as a inverse variation problem or as a uniform rates problem.

As written, n for count of workers, t for time in hours,
{{{n=k/t}}} is the translation of the first sentence.


Second sentence, first part, after solving the formula for k,
{{{k=n*t}}}
{{{k=20*4}}}
{{{k=80}}}


The variation formula can now be more specifically given as {{{n=80/t}}}.


Third sentence, n=25, t is unknown.  Find t.
{{{25=80/t}}}
{{{1/25=t/80}}}
{{{t=80/25}}}
{{{t=16/5}}}
{{{t=3&1/5}}} hours