The IQR or interquartile range is the difference between Q1 and Q3, also know as the upper and lower quartiles.
R = 30 because r = 1,5,10,25
30/5+1=7
6+1=7
0.75 = 3/4
3/4 is your anwer
3 (4x + 6) = 21
4x + 6 = 21/3
4x + 6 = 7
4x = 7 - 6
4x = 1
x = 1/4
