20. $158, 400 - multiply 40 by 22 to get the total square footage(880), then multiply 880 by 15 to get they total for the month, which is 13,200. lastly, you take 13,200 multiplied by 12(for each month in a year), and you get $157,400.
Answer:
x = 1/4
Step-by-step explanation:
<u>Calculations:</u>




Let V, be the rate in still water and let C = rate river current
If the boat is going :
upstream, its rate is V-C and if going
downstream, its rate is V+C,
But V = 5C, then
Upstream Rate: 5C - C = 4 C
Downstream rate: 5C+C = 6C
Time = distance/Rate, (or time = distance/speed) , then:
Upstream time 12/4C and
Downstream time: 12/.6C
Upstream time +downstream time:= 2h30 ' then:
12/4C + 12/.6C = 2.5 hours
3/C + 2/C = 5/2 (2.5 h = 5/2)
Reduce to same denominator :
5C = 10 and Rate of the current = 2 mi/h