Avi and Bindu can complete a project in four and twelve hours, respectively. Avi begins project at 5 a.m., and they work alternately for one hour each. When will the project be completed?

11 a.m.

Avi = 4 hours, Bindu = 12 hours,

⇒ Avi started working at 5 am and they work on alternate hours,

 1st hour = 3 units,

 2nd hour = 1 unit,

 Every 2 hours, 4 units of work is done,

 So, in 6 hours, 12 units of work is completed,

Therefore, 5 am + 6 hours = 11 am.