Someone wanted to bey a new Machine to his factory.
He found three types of machines:-
1-the first type,works 30 Minutes then stops to cool down for 5 Minutes,and works again another 30 Min.,and so on.
2-the second type,works 60 Min.,then stops for 10 Min. to cool down,and so on.
3-the third type,works 90 Min.,makes 15 Min. rest,and so on.
If each product needs 30 Min. to be completely finished with any machine,and the machine should work only 8.5 hours per day.
Which machine should he bey? why?