Al can complete a particular job in 8 hours. Boris can complete the same job in 5. Cody can complete a second job, which requires twice as much work as the first, in 8 hours. If all three people work together on the larger job for 2 hours. How long, in hours, would it take Al, working alone to finish the job?
I am confused as to how to evaluate the 2nd statement "Cody can complete a second job, which requires twice as much work as the first, in 8 hours"
the statement means if A and B are doing work "W" then Cody does a work which is "2W"
Now considering they work at the same workrate A will take 16hrs and B will take 10hrs to do the second job.
In 2hrs A,B and C will complete 2/16 + 2/10 + 2/8 = 92/160 part of the work
remaining work is 1-92/160 = 68/160
A does 1/16 part of second job in 1hr so he would require (68/160)/(1/16) = 6.8hrs