SOLUTION: 1. A scanner can read a stack of sheets in 20 minutes. A second scanner can read the same stack in 12 minutes. How much time would it take for both scanners together to process th

Question 1161170: 1. A scanner can read a stack of sheets in 20 minutes. A second scanner can read the same stack in 12 minutes. How much time would it take for both scanners together to process the one stack of sheets?
My answer is 8 minutes - is that correct?
2. A laborer can do a certain job in 5 days, a second can do the job in 6 days, and a third in 8 days. In what time can the three together do the job?
My answer is 2 days - is that also correct?
Thank you.
Answer by ikleyn(52803) (Show Source): You can put this solution on YOUR website!
.


First scanner makes    of the job per minute.


Second scanner makes    of the job per minute.


Working together, they make   =  =  of the job per minute.


Hence, it will take   =  = 7.5 minutes for two scanners to complete the job working together.

Solved.

-------------------

It is a standard and typical joint work problem.

There is a wide variety of similar solved joint-work problems with detailed explanations in this site. See introductory lessons
    - Using Fractions to solve word problems on joint work
    - Solving more complicated word problems on joint work
    - Selected joint-work word problems from the archive

Read them and get be trained in solving joint-work problems.

Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the topic
"Rate of work and joint work problems" of the section "Word problems".

Save the link to this online textbook together with its description

Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson

to your archive and use it when it is needed.

RELATED QUESTIONS
One optical scanner can read and grade a set of standard answer sheets in; the time it... (answered by ikleyn)

A Photo scanner (A) can scan all the pictures in 2 hours and 15 minutes. Together,... (answered by ikleyn)

A stack of 1/2 plywood is 35 in. high. How many sheets of plywood are in the... (answered by vleith)

Three postal workers can sort a stack of mail in 10 minutes, 20 minutes, and 60 minutes,... (answered by josmiceli)

how many ways can you stack 12 books in a single stack? (answered by stanbon)

how many ways can you stack 12 books in a single... (answered by stanbon)

amber can read 20 pages in 45 minutes how many can she read im an hour and a half (answered by rfer)

solution A is 20% alcohol and solution B is 70% alcohol. How much of each is needed to... (answered by josgarithmetic)

connie can type a stack of reports in 2 hours jerry can type the same stack in 7 hours,... (answered by Alan3354)