10. One printing press can print the first edition of a book in 55 min. A second printing press requires 66 min to pri

10. One printing press can print the first edition of a book in 55 min. A second printing press

requires 66 min to print the same number of copies. How long would it take to print the first

edition of the book with both presses operating?

1 thought on “10. One printing press can print the first edition of a book in 55 min. A second printing press requires 66 min to pri”

1. mocmien2
It would take 30 mins to print the first edition of book with the both press operating.
This can be solved by the  below method :
Typing one edition is 1 job
Machine I does the job in 55 minutes and Machine II does it in 66 minutes.
So,
Part of job in 1 minute of Machine I  = 1/time to complete job 1
= 1/ 55
Part of job in 1 minute of Machine II  = 1/time to complete job 1
= 1/66
Together, both the machines in = 1/55 + 1/66
LCM of 55 and 66 is 3630
With the use of LCM, solve the above equation
= ( 66+55 ) / 3630
= 121/3630
= 1/30  or 30 minutes.
Hence we can say that both the machines together will take 30 minutes to print the first edition of the book.