Question

Sophie is choosing two coins randomly from a box containing four $2, five $1, eight 50 cent and three 20 cent coins. Let X denote Sophie’s income. What are the possible values of X, and what are the probabilities associated with each value?

Answer 1

We have (4+5+8+3) = 20 coins .

to choose 2 out of these 20 , can be done in ways

We make the following table to calculate the possible value s of X and corresponding probability :

Outcome	X	P[X=x]
(2,2)	4
(2,1),(1,2)	3
(2,0.5)(0.5,2)	2.5
(2,0.2),(0.2,2)	2.2
(1,1)	2
(1,0.5)(0.5,1)	1.50
(1,0.2),(0.2,1)	1.20
(0.5,0.5)	1
(0.5,0.2),(0.2,0.5)	0.70
(0.2,0.2)	0.40