Roger started with 90 items in his MP3 collection. Each month, he buys 15 more MP3s to add to his collection. The number of MP3s
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Answer:
The expected value of playing the game is $0.75.
Step-by-step explanation:
The expected value of a random variable is the weighted average of the random variable.
The formula to compute the expected value of a random variable <em>X</em> is:
The random variable <em>X</em> in this case can be defined as the amount won in playing the game.
The probability distribution of <em>X</em> is as follows:
Number on spinner: 1 2 3 4 5 6
Amount earned (<em>X</em>): $1 $4 $7 $10 -$8.75 -$8.75
Probability: 1/6 1/6 1/6 1/6 1/6 1/6
Compute the expected value of <em>X</em> as follows:
Thus, the expected value of playing the game is $0.75.
a) You are told the function is quadratic, so you can write cost (c) in terms of speed (s) as
... c = k·s² + m·s + n
Filling in the given values gives three equations in k, m, and n.
Subtracting each equation from the one after gives
Subtracting the first of these equations from the second gives
Using the next previous equation, we can find m.
Then from the first equation
[tex]28=100\cdot 0.01+10\cdot (-1)+n\\\\n=37[tex]
There are a variety of other ways the equation can be found or the system of equations solved. Any way you do it, you should end with
... c = 0.01s² - s + 37
b) At 150 kph, the cost is predicted to be
... c = 0.01·150² -150 +37 = 112 . . . cents/km
c) The graph shows you need to maintain speed between 40 and 60 kph to keep cost at or below 13 cents/km.
d) The graph has a minimum at 12 cents per km. This model predicts it is not possible to spend only 10 cents per km.
