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3 years ago

A binomial discrete random variable, X has a mean

Mathematics

1 answer:

kompoz [17]3 years ago

5 0

Since X follows a binomial distribution, its mean and variance are

np = 3

np (1 - p) = 2

Substitute np = 3 in to the second equation to solve for p :

3 (1 - p) = 2

1 - p = 2/3

p = 1/3

Solve for n :

n (1/3) = 3

n = 9

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The heights of a maple tree and a cherry tree have a ratio of 5:2. If the maple tree grew 20 cm and 20 cm was cut off the top of

elena-14-01-66 [18.8K]

Let x be the heights of a maple tree and y be the height of the cherry tree.
We know:
 $\frac{x}{y} = \frac{5}{2}$
The new ratio is obtained like this:
 $\frac{x+20}{y-20} = \frac{3}{1}$ .
From the above equation we get $x= (y-20)\frac{3}{1} -20$ .
then $\frac{ (y-20)\frac{3}{1} -20}{y} = \frac{5}{2}$
Solving the above equation for y we get: $y=160$
So $x=400$
So the first tree is (400-160=240) more taller than cherry tree.

7 0

3 years ago

Please solve for w, p=21+2w

sp2606 [1]

Answer:

w = (p - 21)/2

Step-by-step explanation:

Rearrange the equation so that it is equal to w.

p = 21 + 2w

p - 21 = (21 + 2w) - 21

p - 21 = 2w

(p - 21)/2 = (2w)/2

(p - 21)/2 = w

w = (p - 21)/2

3 0

3 years ago

PLEASE HELP WILL CROWNNNNNN!!!!!

Serga [27]

Answer:

- 3

- 8

Step-by-step explanation:

f ( - 2 )

= 2 - 5 ( - 2 )

= 2 - ( - 10 )

= 2 + 10

= 12

f ( - 1 )

= 2 - 5 ( - 1 )

= 2 - ( - 5 )

= 2 + 5

= 7

f ( 0 )

= 2 - 5 ( 0 )

= 2

f ( 1 )

= 2 - 5 ( 1 )

= 2 - 5

= - 5 + 2

= - 3

f ( 2 )

= 2 - 5 ( 2 )

= 2 - 10

= - 10 + 2

= - 8

6 0

3 years ago

What is the value of each expression?

Hunter-Best [27]

Give me points thanks

6 0

3 years ago

Someone plz help me

marusya05 [52]

Answer:

the answer would be 9 I think

5 0

3 years ago