Question 969961
the officejet printer can copy lisa's dissertation in 16 min. the laserjet printer can copy the same document in 18 min. if the two machines work together , how long would they take to copy the dissertation?
***
1/16=work rate of office jet printer
1/18=work rate of laser jet printer
let x=time it would take two machines work together to copy the dissertation.
1/x=their work rate
isum of indv work rates=work rate working together
{{{1/16+1/18=1/x}}}
lcd: 16*18=288
18+16=288/x
34x=288
x=8.47
if the two machines work together , how long would they take to copy the dissertation? 8.47 min