The opportunity cost is the value of the best alternative that is rejected. If Susan goes to college loses what he would win from her salary minus any potential gains from investment in education in college. It can be found as this:
Expenses: 8000 + 900 + 2500 = 11.400
So OCost is: 40.000 - 11.400 = 28600
She would lose 28.600 of income per year because of going to college.
One minute later at 8:01pm. One lighthouse will flash 3 times (at 20, 40 and 60 seconds)...the other will flash twice (at 30 and 60 seconds). So they will both flash 60 seconds later, at 8:01
