How many times must a die be tossed if the expected number of ones is five?
A)5
B)30
C)35
D)6

Question

Quizplus · Accepted Answer

The expected number of ones when a die is tossed once is 1/6. 
Let x be the number of times the die is tossed. 
Then the expected number of ones when the die is tossed x times is (1/6)x. 
We are given that (1/6)x = 5. 
Solving for x, we get x = 30. 
So the die must be tossed 30 times to have an expected number of ones of 5.

How Many Times Must a Die Be Tossed If the Expected