**Please give formulas and step by step instructions**

Burtonsville has minimum requirements for the number of patrol persons on duty during each 4-hour period as shown below. There are no part-time patrol persons and union regulations prohibit split shifts. Each member of the police force works eight consecutive hours. Work out a daily schedule that employs the fewest individuals.

(Shift begins)	Time of Day
X1	12 noon to 4 p.m.	100
X2	4 p.m to 8 p.m.	250
X3	8 p.m. to 12 midnight	400
X4	12 midnight to 4 a.m.	500
X5	4 a.m. to 8 a.m.	200
X6	8 a.m. to 12 noon	150