Question 813821
A,B, or C could finish a job alone in 5 hours.
 The three started together at 8AM but B rested at 9AM and resumed working at 9:30 AM.
 At what time they will finish the work?
:
let t = working time of A & C
then
(t-.5) = working time of b
let the completed job = 1
:
{{{t/5}}} + {{{((t-.5))/5}}} + {{{t/5}}} = 1 
multiply by 5
t + (t-.5) + t = 5
3t = 5 + .5
t = 5.5/3
t = 1.83 hrs or 1 + .83(60) = 1 hr 50 minutes
:
8:00 + 1:50 = 9:50 AM to finish the work