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4 years ago

Mark cycled 25 miles at a rate of 10 miles per hour. How long did it take Mark to cycle 25 miles

Mathematics

1 answer:

otez555 [7]4 years ago

8 0

2.5 hours, because 10 miles an hour times 2 = 20 plus half the time? 2.5

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In a group of 10 kittens, 5 are female. Two kittens are chosen at random. a) Create a probability model for the number of male

olya-2409 [2.1K]

Answer:

(b) Expected number of male kitten E(x) = 1

(c) Standard deviation is ± $\frac{2}{3}$ .

Step-by-step explanation:

Given that,

Number of kittens in a group are 10. Out of these 5 are female.

To find:- (a) create a probability model of male kitten chosen.

So, total number of kitten = 10

number of female kitten = 5

then, Number of male kitten = $10-5= 5$

Now total number of ways to choosing two kittens from group of 10 = $^{10} C_{2}$

= $\frac{10!}{2!\times8!}$

= $45$

for choosing (i) No male P(x=0) = P(Two female) = $\frac{^{5} C_{2}}{45}$

= $\frac{2}{9}$

(ii) 1 male P(x=1) = P(1 male and 1 female) = $\frac{^{5} C_{1}\times^{5} C_{1}}{45}$ = $\frac{25}{45}$ = $\frac{5}{9}$

(iii) 2 male P(x=2)= P(2 male) = $\frac{^{5} C_{2}}{45}$ = $\frac{2}{9}$

$x_{i}$ 0 1 2

P(X= $x_{i}$ ) $\frac{2}{9}$ $\frac{5}{9}$ $\frac{2}{9}$

(b) what is expected number of male kittens chosen ?

Expected number of male kitten E(x) = $o\times \frac{2}{9} + 1\times \frac{5}{9} + 2\times\frac{2}{9}$

= $1$

(c) what is standard deviation ?

$\sigma(x) = \sqrt{ (E(x^{2} )-(Ex)^{2})$

No,

$Ex^{2} =o\times \frac{2}{9} + 1\times \frac{5}{9} + 4\times\frac{2}{9}$

= $\frac{13}{9}$

$\sigma(x)=\sqrt{\frac{13}{9} - 1 }$ $=\sqrt{\frac{4}{9} }$

= ± $\frac{2}{3}$

6 0

3 years ago

Mrs. Patterson’s bakery sells fruit pastries in packages of 15, while chocolate pastries come in packages of 12. What is the sma

Anika [276]

Answer:

For the fruit pastry you will need to buy 4 packages and for the chocolate pastry you will need 5 packages.

Step-by-step explanation:

8 0

3 years ago

I/pai is rational or irrational?

S_A_V [24]

Answer:

Pi is an irrational number

Step-by-step explanation:

Pi is an irrational number, meaning it is a real number that cannot be stated as a fraction. That's because pi is a "infinite decimal," meaning the digits go on forever and ever after the decimal point.

Hope this helps! Have a great day!

6 0

3 years ago

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If Jim Roller can paint a room in 3 hours while John Brush would take 5 hours, how long will they take if they work together?

andrew11 [14]

Answer:

4 hrs

Step-by-step explanation:

half of Jim Rollers time is 1.5 hrs, and half of John Brushs time is 2.5 hrs. The two combined is 4 hrs. Therefore, the answer is four hours.

This is basically finding the average of two numbers, and you can use multiple different equations to find the same answer.

3/2 + 5/2 =4

(3+5)/2 =4

5-3=2, then 2/2=1, 5-1=4

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4 years ago

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Help, my brain is gone and I can't think

crimeas [40]

You can write 1 + -1 as 1 + 1
1 - -1 can be written as 1 +1

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3 years ago