Doris paid $316.80 for wallpaper to cover a 24 foot by 12 foot wall. she used all the wallpaper she purchased, with no waste or overlap.

what was the cost of the wallpaper per square foot?
a. $0.55
b. $1.10
c. $2.20
d. $4.40
e. $8.80

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g