What are the major difference between stone age, bronze age and iron age? How did they impact each other?

No. of Machines Required = 47

Explanation:

First, we calculate the number of parts that can be manufactured by one machine during the shift. For that purpose, we use following formula:

No. of Parts Manufactured by 1 Machine = Total Operating Time/Time taken to perform Operation

where,

Total Operating Time = 8 h - 1 h = (7 h)(60 min/h) = 420 min

Time taken to perform operation = 20 min

Therefore,

No. of Parts Manufactured by 1 Machine = 420 min/20 min

No. of Parts Manufactured by 1 Machine = 21

Now, we will calculate the no. of non-defective parts manufactured by 1 machine. Since, it is given that one-fifth of the parts manufactured by machine are defective. Therefore, the non-defective parts will be: 1 - 1/5 = 4/5 (four-fifth).

No. of Non- Defective Parts Manufactured by 1 Machine = N = (4/5)(21)

N = 16.8 = 16 (Since, the 17th part will not be able to complete in time)

So, the no. of machines required to produce 750 non-defective parts is given by:

No. of Machines Required = No. of non-defective parts required/N

No. of Machines Required = 750/16

No. of Machines Required = 46.9

No. of Machines Required = 47 (Since, 46 machines will not be able complete the job)