How does the mean absolute deviation (mad) of the data in set 1 compare to the mean absolute deviation of the data in set 2? set 1: 5, 10, 7, 2 set 2: 5, 10, 7, 42

Nine more than four times a number is the same as one less than twice the number. find the number?

Look at this pattern ; 1,4,9, number 10000 belongs in this pattern . what’s the place of this number?

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.