Question : A scanner A can scan a document in three hours. Scanner B takes 5 hours to do the same job. If both scanners?
A scanner A can scan a document in three hours. Scanner B takes 5 hours to do the same job. If both scanners are used how long will it take for the document to be scanned?
document scanner

Best answer:

Answer by Pearl_of_Wisdom
1.875 hours

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To arrive at the above answer, you could use this formula…

1 / (A’s time) + 1 / (B’s time) = 1 / (Total time for A and B)

1 / 3 + 1 / 5 = 1 / T

Get a common denominator, so you can add these fractions…

5 / 15 + 3 / 15 = 1/ T
8 / 15 = 1 / T

Cross-multiply, and you get…

8T = 15
T = 15 / 8 (or 1.875) hours

Hope this helps!