The officejet printer can copy Lisa's dissertation in 22 min. The laserjet printer can copy the same document in 18 min. If the two machines work together, how long would they take to print the document?
Algebra/Time - Steve, Tuesday, October 25, 2011 at 12:11pm
1/b = 1/22 + 1/18
b = 22*18/(22+18) = 9.9 min