4. Determine the combination of variables X1, X2, X3, X4 that will maximize profits given this LP Model; Maximize: Z = 34X1 + 18X2 + 27X3 + 40X4 s. t. Labor : X1 + X2 + X3 + X4 ≤ 4000 Product 4: X4 ≤ 500 Machine: 2X1 + X2 + 3X3 ≤ 4200 Material A : 4X2 + 3X4 ≤ 2000 Material B : X1 + X2 + 2X4 ≤ 2300