A joint total revenue functions for sale of the three different microcomputer models are:
TR1 = 500*Q1,
TR2 = 1,000*Q2,
TR3 = 1,500*Q3.
An annual total cost functions for manufacturing the three models:
TC1 = 25,000,000/3 + 275Q1,
TC2 = 25,000,000/3 + 550Q2,
TC3 = 25,000,000/3 + 975Q3.
The profit functions for sales of the three models are:
TP1 = 500Q1 - (25,000,000/3 + 275Q1) = 225Q1 - 25,000,000/3,
TP2 = 1,000Q2 - (25,000,000/3 + 550Q2) = 450Q2 - 25,000,000/3,
TP3 = 1,500Q3 - (25,000,000/3 + 975Q3) = 525Q3 - 25,000,000/3.
TP = 225*20,000 + 450*40,000 + 525*10,000 - 25,000,000 = 2,750,000.