sandy wrote:
A certain machine drills 30 holes in 8 minutes. At that constant rate, how many holes will 4 such machines drill in 113 hours?
(A) 300
(B) 900
(C) 960
(D) 1,200
(E) 2,560
Here
113 = 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=
308Now for the 2nd case
Amount of work = We need to find out
Rate =
308No. of machine = 4
Time = 80 minutes
Therefore
A =R * T
A = 4 *
308 * 80
or A = 1200 holes