Bunuel
At the Scholarly Text Printing Company, each of n printing presses can produce on the average t books every m minutes. If all presses work without interruption, how many hours will be required to produce a run of 10,000 books?
(A) 10,000*60mn/t
(B) 10,000*60tm/n
(C) 10,000mn/(60t)
(D) 10,000m/(60nt)
(E) 10,000/(60mnt)
Algebraic MethodSince 1 printing press produces t books in m minutes, 1 printing press produces \(\frac{t}{m}\) books in a minute.
In an hour, the printing press will produce \(\frac{60t}{m}\) books. 'n' printing presses would produce \(\frac{60nt}{m}\) books per hour.
Therefore, the presses need \(\frac{10000m}{60nt}\) hours
(Option D) to produce 10000 books.
Assuming numbers1 printing press will produce (t = 10) books in (m = 6) minutes.
Therefore, 1 printing press produces \(\frac{5}{3}\) books in a minute.
In an hour, the printing presses will produce \(60(\frac{5}{3}) = 100\) books.
If there are (n=10) machines to do the work, every hour 1000 books are printed
In order to print 10000 books, it took the n printing presses \(\frac{10000}{1000} = 10\) hours.
Substituting the values of t,m,and n in the answer options,
(A) 10,000*60mn/t = 10000*60*6*10/10 = 3600000 hours
(B) 10,000*60tm/n = 10000*60*10*6/10 = 3600000 hours
(C) 10,000mn/(60t) = 10000*10*10/60*6 = 100000/36 hours(D) 10,000m/(60nt) = 10000*6/60*10*10 = 10 hours(E) 10,000/(60mnt) = 10000/60*10*6*10 = 10000/36000 hours (Option D)