Ponyboy regullary takes 4 aspirins, but in Chapter 9 he takes 5 aspirins, why is that?
It is in Chapter 9
"Darry had cooked dinner: baked chicken and potatoes and corn--two chickens because all three of us eat like horses. Especially Darry. But although I love baked chicken, I could hardly swallow any. I swallowed five aspirins, though, when Darry and Soda weren't looking. I do that all the time because I can't sleep very well at night Darry thinks I take just one, but I usually take four. I figured five would keep me going through the rumble and maybe get rid of my headache. "
It is said that he took 5 to face through the rumble, but what kind of other possibilities of reasons why he did it?
At this point in the story, there is a lot going on with Ponyboy. He and his brother had lost their parents only eight months before. He is still reeling from the encounter with the Socs that resulted in Johnny murdering Bob. He and Johnny have been hiding out, their pictures have been printed in the newspaper, and now, he has a rumble to prepare for.
Some of the boys are known for indulging in alcohol and cigarettes. Perhaps Ponyboy used aspirin in this way. For him, it may have acted as a placebo. Of course, aspirin doesn't have a calming effect, but for Ponyboy, it may have been a mind thing. Perhaps self-medicating with the aspirin helped him to deal with all of his anxiety.
I wouldn't say that there was anything more to it than this.
Ponyboy was sick and feeling dizzy but doesn't want Darry to find out because he would not be able to go to the rumble so he ate 5.