Please provide detailed answer, however, in the clearest way as possible, thank very much!

Facts and circumstances: A company produces three different products on several identical machines. The annual capacity is restricted to 12,000 machine hours. The controller has prepared the following overview. Please help her to find out the product mix with the maximum contribution possible using the form below: Required: Which quantities of X,Y and Z should be produced and what would be the maximum contribution? Please provide detailed answer, thanks