Probability Homework Help

Question

A six sided dice and 20 sided dice are rolled.

Let event A be rolling and odd number, and event B be rolling a multiples of 4 on the 20 sided dice.

Determine P(A∩B)

Choices:

-1/120

-7/10

-1/20

-1/10

Answer 1

The correct answer is the last one.

I'm assuming A = rolling an odd number on the six-sided die. Half of the 6 equiprobable outcomes are odd, so P(A) = 1/2

For B, 4/20 or 1/5 of the outcomes are multiples of four, so P(B) = 1/5

A and B are independent. Therefore P(A∩B) = P(A)*P(B) = 1/10