This isn't something specific I need to know for school, I'm just curious. I know the most commonly used variables are x, y, and z. But what if you have more then three variables, what are the next letters you are supposed to use?

Any letter you want

Step-by-step explanation:

The letters used for variables don't matter. What matters is what the variables represent: their numerical value. Variables are just to help identify what needs solving. Other common variables are a, b, and c which are found frequently in trigonometry. To answer your question, there are no "next letters." You can use any letter you'd like as a variable because it holds the same numerical value. Basically, the whole alphabet is at your disposal.

answer:   35 % is the probability of a late departure or an early arrival.

step-by-step explanation:

let l represents the late departure and e represents the early departure.

then, according to the question,

p(l) = 12 %,   p(e) = 27 % and = 4 %

and, we have to find out,

but, we know that,

which is the required equation that will use to find the probability of a late departure or an early departure.

therefore,   the probability of a late departure or an early arrival =   35 %

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