Answer :

prettyroman22
 Clarisse dies (i think). It could be that, in this world, a girl like Clarisse just can’t exist. She’s incompatible with her surroundings, so she’s not allowed to live. I don’t know all the details of her demise, or is the confusion reconciled by the end of the novel. But I can’t help but think of Clarisse when Granger discusses the thumbprint on his mind left by his grandfather. Even after her disappearance/death, Clarisse continues to affect Montag. She exists because she changed his mind, where as someone like Mildred hardly existed at all.
valentinapinzon

The book, Fahrenheit 451, never says if she died or not, but Montag is led to believe she was hit by a car that was street racing. In the play, she's with the hobos at the end. In the book it is said that Clarisse is hit by a moving car and dies. Montag gets this information from his wife Mildred, and is deeply saddened although the information may not be true. In a later, afterward edition she was killed in a car accident

Hope I helped!