The oldest child in a family of four children is twice as old as the yougest. The two middle children are 12 and 15 years old. If the average age of the children is 12.75 , how old is the youngest child?

Agraph of a trapezoid can have diagonals with slopes that are negative reciprocals and two pairs of adjacent sides that are congruent, true or false, and why

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%

Ill mark the brainliest if you me with the these three questions 7,8,9