Question

A single letter from the word ADDITIONALLY is chosen. What is the probability of choosing an A or an I? Express your answer as a fraction in lowest terms or a decimal rounded to the nearest millionth.

Answer 1

The probability of choosing an A is:

`P(A)=(2)/(12)=(1)/(6)`

The probability of choosing an I is:

`P(I)=(2)/(12)=(1)/(6)`

The probability of choosing an A or an I is the sum of both probabilities:

`P(A\cup I)=(1)/(6)+(1)/(6)=(2)/(6)=(1)/(3)`

It means that the answer is 1/3.