Question 1080095: Marco can build a laptop twice as fast as Cliff. Working together, it takes them 5 hours. How long would it have taken Marco working alone? Answer by ikleyn(52799) (Show Source):
Let "m" be the Marco's rate of work.
Then Cliff's rate of work is , according to the condition.
Also, the condition says that
= ,
which means that = , or = , m = = .
Hence, It will take = 7.5 hours for Marko to complete the job working alone.
Answer. It will take 7 hours and 30 minutes for Marko to complete the job working alone.