The mean age of 21 people in a theatre is 18 year-old. One person who is 31 year-old leaves the theatre.

Determine the new mean age of the remaining people.

The sat and act tests use very different grading scales. the sat math scores follow a normal distribution with mean 518 and standard deviation of 118. the act math scores follow a normal distribution with mean 20.7 and standard deviation of 5. suppose regan scores a 754 on the math portion of the sat. how much would her sister veronica need to score on the math portion of the act to meet or beat regan's score?