Answer:
Net cash provided by operating activities for 2018 was $4,560,000 
Explanation:
The net cash provided by operating activities can be computed by preparing the operating activities of the statement of cash flow as shown below:
Net income for the year                          $3,000,000
add depreciation                                      $1,200,000
add amortization                                       $240,000
deduct increase in accounts receivable ($420,000)
add increase in accounts payable           $540,000
net cash provided by operations             $4,560,000  
The cash provided by operating activities is $4,560,000  
The rationale for deducting increase in accounts receivable is that the increase deprived Lindsay corporation cash of $420,000.