Exercise 122 Page 203

Let's first determine the probabilities of rolling each type of side. Probability is calculated by dividing the number of favorable outcomes by the number of possible outcomes. P=Number of favorable outcomes/Number of possible outcomes From the diagram we see that two sides are shaded and four sides are white. If you roll a shaded side, you earn $ 10. Rolling a white side, you earn - $ 5. Let's add this information as well as the probabilities of rolling each type of side to the diagram.

If we multiply the probability of rolling each type of side by what you earn from rolling it and then add these products, we get the expected earnings for one throw. If this sum is 0, it is a fair game. However, first we must calculate the expected earnings for each type of side.

Event	P	earnings	P * earnings	expected earnings
P(white)	2/3	- 5	2/3( -5)	- 10/3
P(shaded)	1/3	10	1/3( 10)	10/3

Let's add the expected earnings from each type of side.

10/3+- 10/3

AddFrac

Add fractions

10+(- 10)/3

AddNeg

a+(- b)=a-b

10-10/3

SubTerm

Subtract term

0/3

CalcQuot

Calculate quotient

0

We are expected to earn $ 0 when rolling the dice. This means it is a fair game.