Mrs. Black, Mrs. Green and Mrs. Gray are in the library. Mrs. Black noticed that the colors of thither 3 hats were the same as their 3 names, but no one was wearing a hat that matched the color of her name. When she told the others this, the woman wearing the green hat told her to be quiet. Which women was wearing the black hat?

The median of a data set is the measure of center that is found by adding the data values and dividing the total by the number of data values that is the value that occurs with the greatest frequency that is the value midway between the maximum and minimum values in the original data set that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude

If the scale factor between two circles is 2x/5y what is the ratio of their areas?

Aquadratic equation in standard from is written ax^2= bx+c, where a, b and c are real numbers and a is not zero?