Hello, mr_motivator!

The tree diagram looks like this . . .A bag contains 4 Red and 3 Green balls.

Helen and Tony play a game where, starting with Helen,

they alternately draw a ball at random and do not replace it.

The game finishes when a Red ball is drawn.

It is decided that each player will receive, from the other units

if they draw the Red ball on the draw.

Construct a table for the random variable representing Helen’s winnings:

thus if Helen draws a Red on the first draw,

if Tony draws it on the next, etc.

Calculate . How much, approximately, would Helen win in a series of 100 games?

. . .

Helen's winnings look like this:

. .

She can expect to win an average of units per game.

In 100 games, she would win about: . units.