Last week Kate Burke ran a 5 kilometer race in 26.688 minutes. This week she ran a race in 24.005 minutes. What is the difference in Kate's times (in minutes)? min

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