Hawkins manufacturing company produces connecting rods for 4- and 6-cylinder automobile engines using the same production line. the cost required to set up the production line to produce the 4-cylinder connecting rods is $1900, and the cost required to set up the production line for the 6-cylinder connecting rods is $3600. manufacturing costs are $14 for each 4-cylinder connecting rod and $19 for each 6-cylinder connecting rod. hawkins makes a decision at the end of each week as to which product will be manufactured the following week. if there is a production changeover from one week to the next, the weekend is used to reconfigure the production line. once the line has been set up, the weekly production capacities are 6100 6-cylinder connecting rods and 7900 4-cylinder connecting rods.
x4 5 the number of 4-cylinder connecting rods produced next week
x6 5 the number of 6-cylinder connecting rods produced next week
s4 5 1 if the production line is set up to produce the 4-cylinder connecting rods; 0 if otherwise
s6 5 1 if the production line is set up to produce the 6-cylinder connecting rods; 0 if
otherwise

a. using the decision variables x4 and s4, write a constraint that sets next week