Answer:
$129,000
Step-by-step explanation:
The indirect method fir calculating cash flows generally starts with net income and then adds or subtracts depending on the non-cash revenue or expense accounts. I.e. it starts at the end and comes back.
In this case, we are starting with net income and we need to add or subtract the changes in accounts receivable. Since accounts receivable decreased during the year it means that more money was collected increasing the cash flow.
Cash flow = net income + change in accounts receivable = $120,000 + ($40,000 - $31,000) = $120,000 + $9,000 = $129,000