There are 4 red cubes, 3 blue cubes, 2 green cubes, and 1 yellow cube. if you pick 2 cubes at random with replacement. what is probability of choosing red, then choosing yellow?

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