Answer:
a. 59.73_3 ft²/h
b. 5.093 h
c. $149.95
Explanation:
a. The specified unit rate is ...
... (square ft)/(hour) = (10.5 ft)(12.8 ft)/(2.25 h) = 134.4 ft²/2.25 h = 59.73_3 ft²/h
b. The wall area is the product of the perimeter of the room and its height:
... A = (2(l+w))h = 2(10.2 ft + 6.7 ft)·(9 ft) = 304.2 ft²
At the above rate, the time required is ...
... (304.2 ft²)/(59.73_3 ft²/h) ≈ 5.093 h
c. If the charge is proportional to the time required, the charge for painting the basement walls will be ...
... $66.25/(2.25 h) = charge/(5.093 h)
... (5.093 h)/(2.25 h)×$66.25 = charge ≈ $149.95
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Note that the number 5.093 shown here is a representation of the number 5.09263392857 used in the calculations. Only the final numbers are rounded in each case.
The underbar in 59.73_3 is a text representation of the overbar usually used to signify the repeating digits in a repeating decimal:
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