this question has been solved before but the solution isn't working so can we please have a different or better solution of possible

QUESTION Zungu Industries is expanding its product line to include three new products: X. Y. and Z. These are to be produced on the same production equipment and the objective is to meet the demands for the three products using overtime where necessary. The demand forecast for the next four months in hours required to make each product is as shown below. Product January February March April X 700 500 900 1000 Y 600 800 700 1200 Z 800 600 800 900 Because the products deteriorate rapidly, there is a high loss in quality and, consequently, a high carrying cost when a product is made and carried in inventory to meet future demand. Each hour's production carried into future months costs R5 per production hour for Model X, R6 for Model Y, and R7 for Model Z. Production can take place either during regular working hours or during overtime. Regular time is paid at R8 when working on X, R9 for Y, and R10 for Z. The overtime premium is 50 percent of the regular time cost per hour. The number of production hours available for regular time and overtime is January February March April Regular time 1500 1300 1800 2000 Overtime 700 650 900 1000 Set up the problem in a spreadsheet and an optimal solution for total cost of the aggregate production plan using the Excel Solver