A radio station has a contest in which contestants roll a regular 6-sided die. If he rolls a 1 or a 2, he wins $50. If he rolls a 3 or a 4, he wins $100. If he rolls a 5, he wins $1000. If he rolls a 6, he doesn't win anything. What is the probability that the first one to win $1000 is the 5th contestant?

Without stratospheric ozone, which of the following would most likely occur? i. smog over major cities would be greatly reduced. ii. farms would produce surplus crops because of increased photosynthesis. iii. uv radiation would damage phytoplankton and reduce populations of aquatic consumers. i only ii only iii only i and ii i and iii