Question 412924
James takes x hours
1/x of the job he does in 1 hour

chris takes x+5 hours
1/(x+5) of the job he does in 1 hour.

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Together they take 3 hours 30 minutes = 3 1/3 hour = 10/3 hours
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so together they do 3/10 of the job in 1 hour

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1/x  +1/(x+5) = 3/10
multiply by LCD 10x(x+5)
10x+50+10x = 3x(x+5)
20x+50 = 3x^2+15x
3x^2+15x-20x-50=0
3x^2-5x-50=0
3x^2-15x+10x-50=0
3x(x-5)+10(x-5)=0
(x-5)(3x+10)=0
x= 5 hours --- james
Chris ---- 10 hours