The square room has a width of 15ft and a height of 10ft. One roll of wall paper is 17.4in by 16.4 ft. How many rolls of wallpaper would it take to cover one wall?

Answer 1

This is an example problems in which the arithmetic solution might not be the answer to the problem.

First an arithmetic:

(15 ft)(10 ft) = 150 ft²

This is the area of the wall

17.4 in = 1.45 ft

(1.45 ft)(16.4 ft) = 23.78 ft²

This is the area of one roll

150 ft² / 23.78 ft² = 6.307

The arithmetic says we need 7 rolls.

Yet this is not reality. Wallpaper is not like paint. Wall paper has seams. And only vertical seams are allowed. This is what happes in real life.

One roll is hung from ceiling to floor. This take 15 ft of the 16.4 ft of the roll. 1.4 ft is waste.

One roll covers 1.45 ft of the 10 ft width.

10 ft / 1.45 ft = 6.897

Although 7 is the answer to the problem the solutions are different.

Answer 2

15 ft by 10 ft = 150 ft^2

17.4/12)(16.4) = 23.78

1.45(16.4) = 23.78

150/23.78 = 6.30782

You need at least 7 rolls

6 won't be enough