Kelly ran 3/8 of a race before resting. Then she ran another 3/8 of the race before resting again. How much of the race, n, does kelly have left to run? Answer

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