Respuesta :

Joe's working rate = 1/16  per hour
Joe's working rate = 1/22 per hour

Let t =  hours spent when working together.
Then
t = 1/(1/16 + 1/22)
  = 1/(0.0625 + 0.0455)
  = 9.263 hours
  = 9 hours + 0.263*60 min
t = 9 hours,  16 minutes 

Answer: 9 hours, 16 minutes