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DaniilM [7]
2 years ago
7

In a class there are 20 students: 3 are 5' 6", 5 are 5'8", 4 are 5'10", 4 are 6', and 4 are 6' 2". A student is chosen at random

. What is the student's expected height?
Mathematics
2 answers:
Tom [10]2 years ago
6 0

Answer:

5'10"

Step-by-step explanation:

Converting  the heights  to inches we have 66, 68, 70, 72 and 74 inches.

Prob(  Choosing 66 student) = 3/20

Prob( Choosing  68"     ..      )  = 5/20 = 1/4.

Prob( Choosing   70" ...      ) = 4/20 = 1'5.

Prob( Choosing     72'     . ...     )  = 4/20 = 1/5.

Prob (Choosing      74"    ....    ) =  4/20 = 1/5.

Expected height =  3/10 *66 + 1/4*68 + 1/5*70 + 1/5*72 + 1/5*74.

= 701/10

= 70.1

= 5'10"

Nutka1998 [239]2 years ago
5 0

Answer:

The student's expected height is 5' 10.1".

Step-by-step explanation:

In a class there are 20 students: 3 are 5' 6", 5 are 5'8", 4 are 5'10", 4 are 6', and 4 are 6' 2".

First we will convert these heights to inches like:

12 inches = 1 feet

5' 6" = 60+6 = 66

5'8" = 60+8 = 68 and so on.

So, we get following heights in inches:

66, 68, 70 ,72, 74

Expected height  = (3/20)66 + (5/20)68 + (4/20)70 + (4/20)72 + (4/20)74 = 70.1 inches.

Or in feet, it will be : 5' 10.1"

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So the probability of rolling a number greater than 2 is 4/6. So 4/6 times 150 should give you the answer 100.
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2 years ago
a lunch stand makes a $.75 profit on each chef's salad and $1.20 profit on each caesar salad. On a typical weekday, it sells bet
tangare [24]

Answer:

<em>50 Chef's salads and 50 Caesar salads should be prepared in order to maximize profit.</em>

Step-by-step explanation:

Suppose, the number of Chef's salad is x and the number of Caesar salad is y

On a typical weekday, it sells between 40 and 60 Chefs salads and between 35 and 50 Caesar salads.

So, the two constraints are:  40\leq x\leq 60 and  35\leq y\leq 50

The total number sold has never exceed 100 salads. So, another constraint will be:   x+y\leq 100

According to the graph of the constraints, the vertices of the common shaded region are:  (40,35), (60,35), (60,40), (50,50) and (40,50)   <em>(Refer to the attached image for the graph)</em>

The lunch stand makes a $.75 profit on each Chef's salad and $1.20 profit on each Caesar salad. So, the profit function will be:  P=0.75x+1.20y

For  (40, 35) ,   P=0.75(40)+1.20(35)=72

For  (60, 35) ,   P=0.75(60)+1.20(35)=87

For  (60, 40) ,   P=0.75(60)+1.20(40)=93

For  (50, 50) ,   P=0.75(50)+1.20(50)=97.5 <u><em>(Maximum)</em></u>

For  (40, 50) ,   P=0.75(40)+1.20(50)=90

Profit will be maximum when x=50 and y=50

Thus, 50 Chef's salads and 50 Caesar salads should be prepared in order to maximize profit.

6 0
2 years ago
Surface-finish defects in a small electric appliance occur at random with a mean rate of 0.3 defects per unit. find the probabil
mario62 [17]

Answer: Probability that a randomly selected unit will contain at least two surface- finish defect is 0.04.

Step-by-step explanation:

Since we have given that

Mean rate defects per unit = 0.3

Since we will use "Poisson distribution":

P(X=K)=\frac{e^{-\lambda}\lambda^k}{k!}

But we need to find the probability that a randomly selected unit will contain at least two surface-finish defect.

P(X\geq 2)=1+P(X=0)+P(X=1)

So,

P(X=0)=\frac{e^{-0.3}0.3^0}{0!}=e^{-0.3}=0.74\\\\P(X=1)=\frac{e^{-0.3}\times 0.3}{1}=0.22

so, it becomes,

P(X>2)=1-(0.74+0.22)=1-0.96=0.04

Hence, probability that a randomly selected unit will contain at least two surface- finish defect is 0.04.

4 0
2 years ago
Easy Car Rental charges $8.50 an hour plus a rental fee of $25.50. Which equation represents the total charges for x hours ?
gladu [14]

Answer:

Total charge = 8.50x + 25.50

Step-by-step explanation:

You multiply the hourly charge($8.50) by the number of hours(x) and add the rental fee($25.50)

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Find the missing length of the triangle.<br> 7.8 ft<br> b<br> 17.8 ft
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What is the perimeter?
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