Answer:
3 equipments
Step-by-step explanation:
each equipment can produce per day:
total second per 8 hour shift = 8 x 60 x 60 = 28,800 seconds
it takes 4,500 seconds to produce 100 units x 95% efficiency = 95 units
then it must be set-up for 3,000 seconds
this process can be completely repeated 3.84 times per day, so the average production per day per equipment = 3.84 x 95 = 364.8 ≈ 364 units
since they need to produce 800 units per day, the manufacturer should purchase = 800 / 364 = 2.2 ⇒ 3 equipments.