You are wallpapering a 10-foot long wall. The wall is 10 feet high, and without doors and windows. The solid-colored wallpaper you've selected is 30 inches wide and comes in 20-foot rolls.

Question

How many widths of paper will it take to cover the wall? How many rolls of wallpaper must you buy to get this total length?

Answer 1

width is 10*12 = 120 inches
So, it takes 120/4 widths

Since the wall is an exact number of widths, we just need to figure the length to find the rolls.

10*12*4 = 480 in long
so, we need 480/(20*12) = 2 rolls

Makes sense, since each roll does 2 strips, and we need 4 strips.