The Office Jet printer can copy Janet's dissertation in 10 min. The Laser Jet printer can copy the same documents in 8 min. If the two machines work together, how long would they take to copy the dissertation?
10*8=80
80/18= 4.4
so it would take 4 min. is this correct?
4 min won't do it. It will take 4.4 as your original calculation shows.
The OfficeJet printer can copy Janet's dissertation in 16 min. The LaserJet printer can copy the same document in 8 min. If the two machines work together, how long would they take to copy the dissertation?
Answer: 5 1/3
No, that is not correct. Let's break down the problem to find the correct answer.
We know that the Office Jet printer can copy Janet's dissertation in 10 minutes and the Laser Jet printer can copy the same document in 8 minutes. When two machines work together, their combined copying rate is faster than when they work individually.
To find out how long it would take for the two machines to copy the dissertation together, we need to calculate their combined copying rate.
The copying rate of the Office Jet printer is 1/10 of the dissertation per minute, and the copying rate of the Laser Jet printer is 1/8 of the dissertation per minute.
To calculate the combined copying rate, we can add the individual copying rates together:
1/10 + 1/8 = 4/40 + 5/40 = 9/40
So, the two machines can copy 9/40 of the dissertation together in one minute.
To find out how long it will take to copy the entire dissertation, we need to divide the total dissertation by the combined copying rate:
1 / (9/40) = 40/9
Therefore, it would take approximately 4.44 minutes (or rounded to the nearest whole number, 5 minutes) for the two machines to copy Janet's dissertation when they are working together.