The HP Officejet H470 Mobile Printer takes twice the time requires by the HP Off

Question

The HP Officejet H470 Mobile Printer takes twice the time requires by the HP Officejet Pro K5400 color printer to photocopy. If, working together, the two machines can complete the job in 45 min, how long would it take each machine, working alone, to copy the brochures?

I know the answers are 135 min. and 67 1 min. but I do not know how to get to each step.

Explanation / Answer

Let H470 and K5400 be called printer P1 and P2 respectively. Time taken by P1 and P2 be t1 and t2 minutes respectively to do job alone. P1 takes twice time of that by P2. So, t1 = 2t2 Both working together takes 45 minutes to do the job. P1 does 1/t1 job in 1 minute and P2 does 1/t2 job in 1 minute. Both in 45 minutes do 45(1/t1 +1/t2) job i.e. full job meaning 1 job. Hence, 45(1/t1+1/t2) = 1 => 45(1/ (2t2) +1/t2) = 1 (since t1 = 2t2) =>45(3/ (2t2)) = 1 => (135/2)/t2 = 1 => t2 = 135/2 = 67.5 minutes. and t1 = 2t2 = 135 minutes. (ANSWER)

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.