Question

Eighty percent of a roof, or 2800 square feet of the roof, has been re-shingled. What is the total area of the roof? a. 22,400 sq ft b. 2240 sq ft c. 3500 sq ft d. 35000 sq ft

Answer 1

Given that "80% of the roof" is same as "2800 square feet of the roof".

Let's consider total area of roof = X square feet.

Then "80 percent of X" = "2800 square feet".

`80\% \;of X = 2800 \;square \;feet \\\\(80)/(100) *X = 2800 \;square \;feet \\\\(4)/(5) *X = 2800 \;square \;feet \\\\X = (5)/(4)* 2800 \;square \;feet \\\\X = (14000)/(4) \;square \;feet \\\\X = 3500 \;square \;feet \\\\`

So total area of the roof would be 3500 square feet.

Hence, option C is correct i.e. 3500 square feet.