sandy wrote:
A certain machine drills 30 holes in 8 minutes. At that constant rate, how many holes will 4 such machines drill in \(1\frac{1}{3}\) hours?
(A) 300
(B) 900
(C) 960
(D) 1,200
(E) 2,560
Here \(1\frac{1}{3}\) = 80minutes
Therefore we KNow-
Amount of work = Rate * Time
Amount of work = 30 holes
Rate = we need to find it
Time = 8 minutes
No. of machine = 1
so in first case
30 = 1 * R * 8
or Rate= \(\frac{30}{8}\)
Now for the 2nd case
Amount of work = We need to find out
Rate = \(\frac{30}{8}\)
No. of machine = 4
Time = 80 minutes
Therefore
A =R * T
A = 4 * \(\frac{30}{8}\) * 80
or A = 1200 holes
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