Question 279511
x/30+x/45+x/90=1
3x+2x+x=90
6x=90
2x=30
x=15 minutes working together
check
15/30+15/45+15/90=1

1/2+1/3+1/6=1
3/6+2/6+1/6=1
John does 1/2 of the work three times Tom's portion
Julie does twice as much as Tom