You want the largest SQUARE floor then both of the sides have to be the same. Since one gallon can cover up 144 square feet, to work out the dimensions you have to find the square root of 144 which is 12. So the largest square floor it can cover has dimensions 12x12 feet.
Hope this helped :)
The quick way to do this is to multiply the bill by 1, mult. it again by 0.18, and then add the two results together.
Better and faster: Mult. the bill amount ($42.75) by 1.18:
1.18($42.75) = $50.45 (answer)
Im pretty sure it’s going to be a, because when you divide by the -6 you’re supposed to switch the sign
