If we take 24 h, and think that 150 bolts are produced during 1 hour,
then during 24 hours we will get 150*24 = 3600 bolts.
So, y = 150x represent the number of bolts the machine can produce in x hours.
150 bolts/h, and y =150bolts/h *24 h = 3600 bolts
Answer is B.