Colton sold a total of 28 tee shirts and sweatshirts as a fundraiser for his football team. If tee shirts cost 12 dollars each and sweatshirts cost 20 dollars each and he raised a total of 424 dollars how many tee shirts did he sell?

Plzzz plzz maths ! quadratic sequences =an^2+bn 1) 1,6,15,28,45 2)5,18,39,68,105 3) 1,8,21,40,65 4) 7,24,51,88,135 5) -1,2,9,20,35

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%

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle