Jackie is knitting a scarf and wants to know the unit rate of stitches per inch. If she knits 105 stitches to create a 5-inch section of the scarf, what is the unit rate of stitches per inch?
To find the unit rate, divide the total number of stitches by the length in inches.
The unit rate of stitches per inch is 105 stitches / 5 inches = <<105/5=21>>21 stitches per inch. Answer: \boxed{21}.