find how much work they get done in 1 hour
jackie takes 5 hours to do 1 room, so in 1 hour, she does 1/5 room
voilet take 6 hours to do 1 room so in 1 hour, she does 1/6 room
together, they do 1/5+1/6 room in 1 hour
make common denom
1/5+1/6=6/30+5/30=11/30 in 1 hour
11/30 times time=1 room
times both sides by 30/11
time=30/11 hour
time=2 and 8/11 hour
that is about 2 hours and 44 mins
2 and 8/11 hour or 30/11 hours