How pay for workers is determined?

Which of the following has the largest impact on opportunity cost

You are the manager of a large crude-oil refinery. as part of the refining process, a certain heat exchanger (operated at high temperatures and with abrasive material flowing through it) must be replaced every year. the replacement and downtime cost in the first year is $165 comma 000. this cost is expected to increase due to inflation at a rate of 7% per year for six years (i.e. until the eoy 7), at which time this particular heat exchanger will no longer be needed. if the company's cost of capital is 15% per year, how much could you afford to spend for a higher quality heat exchanger so that these annual replacement and downtime costs could be eliminated?

The following information is needed to reconcile the cash balance for gourmet catering services.* a deposit of $5,600 is in transit.* outstanding checks total $1,000.* the book balance is $6,400 at february 28, 2019.* the bookkeeper recorded a $1,800 check as $17,200 in payment of the current month's rent.* the bank balance at february 28, 2019 was $17,410.* a deposit of $400 was credited by the bank for $4,000.* a customer's check for $3,300 was returned for nonsufficient funds.* the bank service charge is $90.what was the adjusted book balance?