Question

A homeowner plans to hang wallpaper on one wall of a bedroom that is 10 feet long

Answer 1

You didn't type rest of answer but here
Draw a diagram to illustrate the problem.
Let n = number of strips required.

Note that 10 feet = 10*12 = 120 inches.
Because each strip is 20 inches wide, therefore
20n = 120
n = 120/20 = 6

Answer: 6 strips