SOLUTION: Machine A can produce 40 bolts per minute whereas Machine B can produce only 30 per minute. Machine A begins alone to make bolts but it breaks down after 1 1/2 minutes and Machine

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Machine A can produce 40 bolts per minute whereas Machine B can produce only 30 per minute. Machine A begins alone to make bolts but it breaks down after 1 1/2 minutes and Machine       Log On


   



Question 768206: Machine A can produce 40 bolts per minute whereas Machine B can produce only 30 per minute. Machine A begins alone to make bolts but it breaks down after 1 1/2 minutes and Machine B must complete the job. If the job requires 300 bolts how long does the whole operation take?
A) 7 1/2 minutes
B) 8 minutes
C) 8 1/2 minutes
D) 9 minutes
E) 9 1/2 minutes

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
In +1.5+ min, machine A produces
+40%2A1.5+=+60+ bolts
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Now, machine B must produce
+300+-+60+=+240+ bolts
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For machine B,
( number of bolts produced ) = ( rate of producing )*( time spent producing )
Let +t+ = B's time in mins
+240+=+30%2At+
+t+=+240%2F30+
+t+=+8+ min
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The total time to produce 300 bolts is:
+1.5+%2B+8+=+9.5+ min