Question 807907
First we must figure how how long it will take them to get the job done if they work together.


1/5+1/8+1/10 = 1/t


8/40+5/40+4/40 = 1/t


(8+5+4)/40 = 1/t


17/40 = 1/t


17t = 40*1


17t = 40


t = 40/17


It will take 40/17 days (roughly 2.3529 days) if they work together.


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Now divide 40/17 by 5 to figure out what fraction Peter gets done when the 3 work together.


(40/17)/5


(40/17)/(5/1)


(40/17)*(1/5)


(40*1)/(17*5)


(40)/(85)


8/17



Final Answer: Peter completes <font color="red">8/17</font> of the job over the entire period of 40/17 = 2.3529 days when all 3 work together.