Answer:
6 hours
Step-by-step explanation:
Let x represent the time in hours it takes the second worker to do the job alone. Then each hour, 1/x of the job gets done by that worker. Similarly, the regular custodian accomplishes 1/3 of the job in each hour. Working together, they do 1/2 of the job each hour:
1/3 +1/x = 1/2
1/x = 1/2 -1/3 = 3/6 -2/6 = 1/6 . . . . subtract 1/3 and simplify
x = 6
It takes the second worker 6 hours to do the same job alone.
