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3 years ago

In a class, 40% of the students are boys. There are 22 boys in the class. How many students are in the class?

Mathematics

1 answer:

Readme [11.4K]3 years ago

6 0

40/100 = 22/x
40x = 2200
x = 55
There are 55 students in this class.

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2.375 divided by 0.05

Xelga [282]

Well, you calculate 237.5 divided by 5. This is 47.5.

4 0

3 years ago

g red bell pepper seeds germinates 85% of the time. planted 25 seeds. What is the probability that 20 or more germinate

bixtya [17]

Answer:

$P(X\geq 20)= P(X=20)+P(X=21)+P(X=22)+P(X=23)+P(X=24)+P(X=25)$

And replacing using the mass function we got:

$P(X=20)=(25C20)(0.85)^{20} (1-0.85)^{25-20}=0.156$

$P(X=21)=(25C21)(0.85)^{21} (1-0.85)^{25-21}=0.211$

$P(X=22)=(25C22)(0.85)^{22} (1-0.85)^{25-22}=0.217$

$P(X=23)=(25C23)(0.85)^{23} (1-0.85)^{25-23}=0.161$

$P(X=24)=(25C24)(0.85)^{24} (1-0.85)^{25-24}=0.0759$

$P(X=25)=(25C25)(0.85)^{25} (1-0.85)^{25-25}=0.0172$

And adding the values we got:

$P(X\geq 20) = 0.8381$

Step-by-step explanation:

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=25, p=0.85)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

We want to find the following probability:

$P(X\geq 20)= P(X=20)+P(X=21)+P(X=22)+P(X=23)+P(X=24)+P(X=25)$

And replacing using the mass function we got:

$P(X=20)=(25C20)(0.85)^{20} (1-0.85)^{25-20}=0.156$

$P(X=21)=(25C21)(0.85)^{21} (1-0.85)^{25-21}=0.211$

$P(X=22)=(25C22)(0.85)^{22} (1-0.85)^{25-22}=0.217$

$P(X=23)=(25C23)(0.85)^{23} (1-0.85)^{25-23}=0.161$

$P(X=24)=(25C24)(0.85)^{24} (1-0.85)^{25-24}=0.0759$

$P(X=25)=(25C25)(0.85)^{25} (1-0.85)^{25-25}=0.0172$

And adding the values we got:

$P(X\geq 20) = 0.8381$

7 0

3 years ago

A rubber of length 89m is cut into 3 equal pieces. What is the length of each piece.

borishaifa [10]

Answer: i dont see the answer listed. The answer is 29 ²/₃m

Step-by-step explanation:

89m long piece of rubber is cut into 3 pieces. In other words, divided into 3 pieces.

89m ÷ 3 = 29.66666666m

Which concerts to 29²/₃m

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3 years ago

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denis-greek [22]

Answer:

C- The surface area is increased by 4 times

Step-by-step explanation:

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3 years ago

Read 2 more answers

Find the solution to each equation mentally or use your calculator. (Hint: do the opposite of the number on the left side of the

il63 [147K]

Answer:

A. 10

B. 300

C. -3

D. -3,567

Step-by-step explanation:

im pretty sure this is coreect i apologize if not

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3 years ago