- #1

TheMathNoob

- 189

- 4

## Homework Statement

A box contains three cards. One card is red on both sides, one card is green on both sides, and one card is red on one side and green on the other. One card is selected from the box at random, and the color on one side is observed. If this side is green, what is the probability that the other side of the card is also green?

## Homework Equations

P(BlA)=P(AnB)/P(A)

## The Attempt at a Solution

Why intuitively the prob is not 1/2?

If you pick one card and notice the the first side is green then the prob that other side is green too would be 1/2 because there are just 2 cards that have green sides.