Question 450436
It takes Jon 75 minutes to paint a room.
 It takes Jeff 60 minutes and Jackie 80 minutes each to paint the same room.
 How long will the painting take if all three work together? 
:
Let t = time required when all work together
Let the completed job = 1
:
A typical shared work equation
:
{{{t/75 + t/60 + t/80}}} = 1
:
multiply by 1200 to clear the denominators, results:
16t + 20t + 15t = 1200
51t = 1200
t = {{{1200/51}}}
t = 23.53 min all working together