Kalyan singhal corp. makes three products, and it has three machines available as resources as given in the following lp problem: maximize contribution = 6x1 + 8x2 + 4x3subject to: 1x1 + 7x2 + 4x3 < = 72(hours on machine 1)2x1 + 1x2 + 7x3 < = 76 (hours on machine 2)8x1 + 4x2 + 1x3 < = 72 (hours on machine 3)x1, x2, x3 > =0(a) determine the optimal solution using lp software. (b) is there unused time available on any of the machines with the optimal solution? (c) what would it be worth to the firm to make an additional hour of time available on the third machine?