Question 246540
Let x=amount of time it takes if both machines are working together
Then together the machines copy at the rate of 1/x of the dissertation per min
Officejet copies at the rate of 1/22 of the dissertation  per min
Laserjet copies at the rate of 1/16 dissertation per min
Together they copy at the rate of 1/22 + 1/16 of the dissertation per min
So, our equation to solve is:
1/22 + 1/16=1/x multiply each term by 176x

8x+11x=176
19x=176 or
x=176/19 or 9.263 minutes------------------time needed if both machines work together

CK
In (176/19) min, the officejet copies (1/22)(176/19) =8/19 of the dissertation
In (176/19) min, the laserjet copies (1/16)(176/19) =11/19 of the dissertaion
8/19 + 11/19=19/19 or 1 dissertation

Hope this helps---ptaylor