Question 900179
You can think of this tank or pool filling as a doing a job or a work problem with uniform rates.


RT=J and 1 job is "fill the pool".


Rates:
Regular pump, {{{1/10}}}
Slower pump, {{{1/x}}}
Combined pumps, {{{1/6}}}


You only have the addition of rates, because they are like "moving in the same direction" when they work together.


{{{highlight_green(1/10+1/x=1/6)}}}
LCD is 30x.
Multiply both sides by 30x.
{{{3x+30=5x}}}
{{{30=2x}}}
{{{highlight(x=15)}}}------The time in HOURS for the slower pump to fill the pool if working alone.