Answer:
16 hours
Step-by-step explanation:
In the time it took Ruth to plant 5 bulbs, Terry planted 3 bulbs. So, Terry did 3/8 of the work of planting 8 bulbs in that time.
We expect that Terry alone would take 8/3 of the time that it took when working together with Ruth.
(8/3)×(6 hours) = 16 hours . . . . . . for Terry to do the job alone