Abag has 2 yellow marbles and 10 brown marbles. half of the brown marbles are made of glass. a marble is selected at random from the bag. what is the probability that it is a brown, glass marble?

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