How to find the percentage of a number?

Which number produces a rationale number when multiplied by 1/5

The box plots show the average speeds, in miles per hour, for the race cars in two different races. which correctly describes the consistency of the speeds of the cars in the two races?

Me its important ! marge runs an ice cream parlor. her speciality is triple chocolate sundaes.she can prepare 1 sundae every 2 minutes, and she earns $1.20 for each sundae she makes . if she just makes sundaes for a single shift of at most 4 hours and at least 2 hours , which function relates her earnings to the number of minutes she works?