Alex can pour on a walkway in x hours alone while Andy can pour concrete on the same way in two more hours than Alex.

a. How fast can they pour concrete on the walkway if they work together?

b. If Emman can pour concrete on the same walkway in one more hour than Alex, and Roger can pour the same walkway in one hour less than Andy, who must work together to finish the job with the least time?

My answer:

the work is the time times rate... therefore

a. Alex + Andy = 1/x + 1/(x+2) ...

b. Emman + Roger = 1/ [(x+2)+1] + 1/[(x+2) - 1] or 1/(x+3) + 1/(x+1)

=== I think the pair who can work with the lesser time is Alex and Andy.

Hope you guys will check my work.. thanks a lot ...

God Bless. Thank you.