Question 248606
Let x=amount of time it takes both working together to do the route
Then both working together does 1/x of the route per min

Trent does 1/30 of his route per min
Lois does 1/20 of the route per min
so, our equation to solve is
1/30 + 1/20=1/x  multiply each term by 60x
2x+3x=60
5x=60
x=12 min---------------------time it take both working together
CK
In 12 min, Trent does (1/30)*12=12/30=2/5 of the route
In 12 min, Lois does (1/20)*12=12/20=3/5 of the route
2/5 + 3/5=5/5 or the whole route

Hope this helps---ptaylor