I"m having a hard time setting up the 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?
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