For a box plot the range is 18 and the interquatile range is 7 what is the difference?

The range is the difference between the maximum number and the minimum number. From the picture, the range is: 34 - 16 = 18
The interquartile range is the difference between Q3 and Q1 values. From the picture, the IQR is: 29 - 21 = 8
The difference between these values is: 18 - 8 = 10