What is the reciprocal of the fraction 4 3/7

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

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%

To determine the number of deer in a forest a forest ranger tags 280 and releases them back