If QR=17 and PR=21 find PQ

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

How to use order of operation in 20 divide by 4 multiply 5 = 1

The table showed price paid per concert ticket on a popular online auction site. what was the average price paid per ticket