Answer:
Cash flow from investing activities  
Cash received from sale of truck	= $8,600
Cash received from sale of machine = $5,600
Cash paid for purchase of investment  = -$16,300
Net cash used by investing activities = ($2,100)
Explanation:
Given: 
a. Sold a truck costing $40,000, with $22,000 of accumulated depreciation, for $8,000 cash. The sale results in a $10,000 loss.
b. Sold a machine costing $10,000, with $8,000 of accumulated depreciation, for $5,000 cash. The sale results in a $3,000 gain
c. Purchased stock investments for $16,000 cash. The purchaser believes the stock is worth at least $30,000 
Cash flow from investing activities  
Cash received from sale of truck	= $8,600
Cash received from sale of machine = $5,600
Cash paid for purchase of investment  = -$16,300
Net cash used by investing activities = ($2,100)