Answer and Explanation:
1. Gain on sale of land 
 It is come from 
= Sale value - book value 
= $240,000 - $200,000
= $40,000
Since there is a gain of $40,000 which is to be deducted from a net income under the cash flow from operations
2. Cash received from sale of land 
The cash is received from sale of land reflects that the cash is come i.e inflow of cash and the same is to be reflected under the cash flow from investing activities in a positive amount i.e $240,000
3. Cash paid for purchase of land 
The cash is paid for purchase of land reflects that the cash is gone i.e outflow of cash and the same is to be reflected under the cash flow from investing activities in a negative amount i.e -$400,000