Emily's vacuum has a power rating of 200w if the vacuum cleaner does 36j of work how long did emily spend vacuuming

                                               Power = (work) / (time)

Multiply each side by (time):    (power) x (time) = (work)

Divide each side by (power):      time = (work) / (power) =

                                                      (360,000 J) / (200 W) = 1,800 sec

                                                                                         =  30 minutes