Answer and Explanation:
The preparation of the incremental analysis is shown below:
 Incremental analysis 
 Particulars Normal Additional Total 
Revenue $4,500,000 $360,000 $4,860,000 
 (30,000 units × $12)
Less: expenses 
Material $600,000 $60,000 $660,000 
 ($600,000 ÷ 300,000 × 30,000 units)
Labor $1,200,000 $120,000 $1,320,000 
 ($1,200,000 ÷ 300,000 × 30,000 units)
Overhead $300,000 $45,000 $345,000 
 ($300,000 × 15%) 
Selling expenses $450,000 $0 $450,000 
Admin expenses $771,000 $129,000 $900,000 
Net income $1,179,000 $6,000 $1,185,000
Since the net income is increased by $6,000 so the company should accept the offer