The number of copies made each week by teachers at Lamley High School follows a bell-shaped distribution with a
1 answer:
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Answer:
- Josh's book lands first
- Ben's lands about 0.648 seconds later
Step-by-step explanation:
Using the given equation for v=60 and s=40, the height of Ben's book is ...
h(t) = -16t² +60t +40
We want to find t when h(t) = 0, so we're looking for the solution to ....
0 = -16t² +60t +40
Using the quadratic formula, we find the positive value of t to be ...
t = (-60 -√(60² -4(-16)(40)))/(2(-16)) = (15 +√385)/8 ≈ 4.3277
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Similarly, the height of Josh's book is ...
0 = -16t² +48t +40
t = (-48 -√(48² -4(-16)(40)))/(2(-16)) = (12 +√304)/8 ≈ 3.6794
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The time before Josh's book lands is shorter by ...
4.3277 -3.6794 ≈ 0.6482 . . . . . seconds
Josh's book reaches the ground first, by about 0.648 seconds.
1) 4.55
2) Short hit
Step-by-step explanation:
1)
The table containing the score and the relative probability of each score is:
Score 3 4 5 6 7
Probability 0.15 0.40 0.25 0.15 0.05
Here we call
X = Miguel's score on the Water Hole
The expected value of a certain variable X is given by:
where
are all the possible values that the variable X can take
is the probability that
Therefore in this problem, the expected value of MIguel's score is given by:
2)
In this problem, we call:
X = Miguel's score on the Water Hole
Here we have that:
- If the long hit is successfull, the expected value of X is
- Instead, if the long hit fails, the expected value of X is
Here we also know that the probability of a successfull long hit is
Which means that the probabilty of an unsuccessfull long hit is
Therefore, the expected value of X if Miguel chooses the long hit approach is:
In part 1) of the problem, we saw that the expected value for the short hit was instead
Since the expected value for X is lower (=better) for the short hit approach, we can say that the short hit approach is better.