Please help me, I'm having a hard time setting up this problem.
George can plant a garden in 2 hours, and it takes Joyce 3 hours. They work together for 45 mins, and George leaves and Joyce finishes the job alone. How long does it take Joyce to finish planting the garden?
Well, if you didn't like Reiny's solution, how about this?
George can plant 1/120 garden in one minute
Joyce can plant 1/180 garden in one minute
In 45 minutes, they can together plant
45/120 + 45/180 = 3/8 + 1/4 = 5/8 garden
That leaves 3/8 garden for Joyce to plant.
3/8 ÷ 1/180 = 67.5 minutes