Sam is training for a triathlon, a timed race that combines swimming, biking, and running. Because his pool sessions are helping him swim more quickly, Sam plans to reduce by 1 hour per week the time he spends training on the bike and increase by 1 hour the time he spends in the swimming pool; however, his wife says that he should stop doing any biking and running and spend all 20 hours per week in the pool. Which basic principle of individual choice does this scenario illustrate? a. Many decisions are made on the margin.
b. People usually exploit opportunities to make themselves better off.
c. Resources are scarce.
d. All costs are opportunity costs.

Expert computers was started in 2018. the company experienced the following accounting events during its first year of operation: started business when it acquired $40,000 cash from the issue of common stock. purchased merchandise with a list price of $32,000 on account, terms 2/10, n/30. paid off one-half of the accounts payable balance within the discount period. sold merchandise on account for $28,000. credit terms were 1/20, n/30. the merchandise had cost expert computers $16,000. collected cash from the account receivable within the discount period. paid $2,100 cash for operating expenses. paid the balance due on accounts payable. the payment was not made within the discount period. required record the events in a horizontal statements model below. in the cash flows column, use the letters oa to designate operating activity, ia for investing activity, fa for financing activity, or nc for net change in cash. if the account is not affected by the event, leave the cell blank. the first event is recorded as an example. what is the amount of gross margin for the period? what is the net income for the period?