Question 387668
Add their rates of emptying to get rate for both
In words:
{1 pool)/(6 hours) + (1 pool)/(9 hours) = (1 pool)/(x hours)
{{{1/6 + 1/9 = 1/x}}}
Multiply both sides by {{{18x}}}
{{{3x + 2x = 18}}}
{{{5x = 18}}}
{{{x = 3.6}}}
It will take 3.6 hrs or 3 hours and 36 minutes