Which number is not in scientific notation? 11 ⋅ 1021 5.7 ⋅ 109 3.1 ⋅ 10−12 1.67 ⋅ 10−5

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Two years ago a man was six times as old as his daughter. in 18 years he will be twice as old as his daughter. determine their present ages.

Asunflower was 20 1/2 inches tall. over the next 6 months, it grew to a height of 37 inches tall. what was the average yearly growth rate of the height of the sunflower? ? plz write a proportion to solve i will give you 100 points