Corbin has pens. There are three types of pens: red, black, and blue. If the probability of getting a red pen is 4/10 and the probability of getting black is 5/10, what is the probability of getting blue?

( I really need this answered or else I might not pass this year pls help! simplify if u can. Hint: It'll be a fraction, I know this because I have to match the fraction to the problem. For whoever helps me I'm forever grateful and thanks so much!)