A group of your friends participated in a cleanup day at a local park, part of a volunteering competition between schools. A few tasks didn't require any expertise, but most were completed by your friends who have experience in carpentry (Troy and Amanda), painting (Jake and Colleen), and gardening (Morgan and Brian).
They recorded the person-hours spent at each task. For example, 6 person-hours could mean that one of your friends worked for six hours, or two friends worked three hours each. When a task was split across multiple people, everyone started and completed the task at the same time, and no task was ever left partially completed at any time.
They kept track of how long each task took, but the competition paperwork requires a timeline of the work done by each volunteer. With what your friends remember about the day, can you put together a timeline for each person?
Troy: "The bridge is at the start of the trail, so that had to be repaired first. Then trail maintenance could be done, and finally that sign could be replaced."
Colleen: "We knew we'd be the last step on a lot of tasks. The trail sign could only be painted once it was rebuilt, same with the park bench and the fence."
Brian: "The day lasted from 9 AM to 5 PM. Everyone got done right at noon, so we all broke for lunch for half an hour."
Morgan: "There was a lot of underbrush that needed to be removed, so we did that first. That got cleaned up during leaf raking and was taken to be mulched on the gardening supply run. Then the flower beds had to be weeded before flower planting, and finally mulch spreading."
Amanda: "I repaired the fence when we split up."
Jake: "All the supply runs needed two people. The painters and carpenters couldn't do anything without the donated supplies, so we went first thing. The gardeners could start right away. They just needed the flowers and mulch to be picked up at some point."