Question 851865
A garden hose can fill up a hot tub in 270 minutes, whereas the drain can empty in 450 mins. If the drain is left open how long will it take to fill the tub.
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let x=time it will take to fill the tub
1/270=rate at which hose can fill tub by itself
1/450=rate at which tub will empty by open drain
1/x=rate at which tub will fill with input from garden hose and drain open.
sum of individual work rates=work rate working together
{{{1/270-1/450=1/x}}}
LCD:x(270)(450)
450x-270x=270*450
180x=121500
x=675
time it will take to fill the tub=675 min