Jd group produces two types of desks: standard and executive. these desks are sold to russell's furniture and for all practical purposes, there in an unlimited market for any mix of these desks, at least within jd group's production capacity. each desk has to go through four basic operations: cutting of the lumber, joining of the pieces, pre-finishing, and final finish. each unit of the standard desk produced takes 48 minutes of cutting time, 2 hours of joining, 40 minutes of pre-finishing, and 4 hours of final finishing time. each unit of the executive desk requires 72 minutes of cutting, 3 hours of joining, 2 hours of pre-finishing and 5 hours and 20 minutes of final finishing time. the daily capacity for each operation amounts to 16 hours of cutting, 30 hours of joining, 16 hours of pre-finishing and 64 hours of final finishing time. the profit per unit produced is r40 for the standard desk and r50 for the executive desk. determine the product mix that maximizes total revenue.