Answer:
Joe: 3 hrs
Janet: 6hrs
Step-by-step explanation:
joe takes x hours
so in 1 hr he does 1/x of the garden
janet takes 2x hours
so in 1 hr she does 1/(2x) of the garden
In one hour together they do 1/2 of the garden
1/x + 1/(2x) = 1/2
2/(2x) + 1/(2x) = 1/2
3/(2x) = 1/2
Cross multiply
6 = 2x
x = 3
Joe: 3 hrs
Janet: 6hrs