Find percent of each number
1) 5% of 40
2) 250% of 44
3) 0.5% of 13.5
4) 32% of 54

What expression is equivalent to 42x-56y

What is r i 4.5+10r=-6.5 with work pls

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