carpenter sells 3, 5 or 9-meter long finished products cut from 17-meter long logs. The demand is 25 for 3-meter products, 20 for 5-meter and 15 for 9-meter products. Using the decision variables given below (do not define other decision variables), write a linear mathematical model to minimize the number of logs (thus waste) used. Xij = Number of i-type products (3-meter, 5-meter or 9-meter) produced from the jlog. Assume there are 30 logs in your inventory, j=1,..., 30. Y= 1 if j 17-meter log is used; 0 otherwise.