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3 years ago

A building company completes 42 homes every 2 months.

Mathematics

1 answer:

luda_lava [24]3 years ago

5 0

Answer:

126

Step-by-step explanation:

if they can do 42 houses in 2 months we need to find out how many houses they can complete in 1 month

$42 / 2 = 21$

so they can build 21 houses in 1 month and we need to find out how many they can build in 6 months

$21*6 = 126$

they can complete 126 homes in 6 months

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PLEEEASE HELLLLP!!!!!!! If x+7=2y and y=2x−1, what is the value of y?

viktelen [127]

Answer:

Step-by-step explanation:

We can add 1 to both sides of the second equation and divide by 2 to get

x = (y-1)/2

We can then substitute x in the first equation to get

(y-1)/2 + 7 = 2y

Multiply by 2

y-1 + 14 = 2y

Subtract y and combine like terms

y = 13

6 0

4 years ago

the wheel of a unicycle has a radius of 14 inches. About how many rotations will it take for the unicyle to tavel 440 inches

sdas [7]

31 rotations, hope i was a big help to you

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4 years ago

Help! Math Homework.

Alenkinab [10]

To solve problem 1 what you need to do is figure out how many miles the girls have walked so far and then subtract that from the total distance they must complete.

3/4-(3/10+1/4)

Step 1:Change the denominators so that way they are all the same

3/4=15/20
3/10=6/20 15/20-(6/20+5/20)
1/4=5/20

Step 2: Begin solving the problem

6/20+5/20=11/20
15/20-11/20=4/20

Step 3: Simplify your answer

4/20=1/5

Step 4 (is optional): Write your answer in a complete statement

The three girls walk 1/5mile together to school

Answer: A

I hope this is correct and if not I apologize for giving false information.

8 0

3 years ago

It is estimated that 75% of all young adults between the ages of 18-35 do not have a landline in their homes and only use a cell

Mademuasel [1]

Answer:

a) 75

b) 4.33

c) 0.75

d) $3.2 \times 10^{-13}$ probability that no one in a simple random sample of 100 young adults owns a landline

e) $6.2 \times 10^{-61}$ probability that everyone in a simple random sample of 100 young adults owns a landline.

f) Binomial, with $n = 100, p = 0.75$

g) $4.5 \times 10^{-8}$ probability that exactly half the young adults in a simple random sample of 100 do not own a landline.

Step-by-step explanation:

For each young adult, there are only two possible outcomes. Either they do not own a landline, or they do. The probability of an young adult not having a landline is independent of any other adult, which means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

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

And p is the probability of X happening.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

75% of all young adults between the ages of 18-35 do not have a landline in their homes and only use a cell phone at home.

This means that $p = 0.75$

(a) On average, how many young adults do not own a landline in a random sample of 100?

Sample of 100, so $n = 100$

$E(X) = np = 100(0.75) = 75$

(b) What is the standard deviation of probability of young adults who do not own a landline in a simple random sample of 100?

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{100(0.75)(0.25)} = 4.33$

(c) What is the proportion of young adults who do not own a landline?

The estimation, of 75% = 0.75.

(d) What is the probability that no one in a simple random sample of 100 young adults owns a landline?

This is P(X = 100), that is, all do not own. So

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 100) = C_{100,100}.(0.75)^{100}.(0.25)^{0} = 3.2 \times 10^{-13}$

$3.2 \times 10^{-13}$ probability that no one in a simple random sample of 100 young adults owns a landline.

(e) What is the probability that everyone in a simple random sample of 100 young adults owns a landline?

This is P(X = 0), that is, all own. So

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{100,0}.(0.75)^{0}.(0.25)^{100} = 6.2 \times 10^{-61}$

$6.2 \times 10^{-61}$ probability that everyone in a simple random sample of 100 young adults owns a landline.

(f) What is the distribution of the number of young adults in a sample of 100 who do not own a landline?

Binomial, with $n = 100, p = 0.75$

(g) What is the probability that exactly half the young adults in a simple random sample of 100 do not own a landline?

This is P(X = 50). So

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 50) = C_{100,50}.(0.75)^{50}.(0.25)^{50} = 4.5 \times 10^{-8}$

$4.5 \times 10^{-8}$ probability that exactly half the young adults in a simple random sample of 100 do not own a landline.

8 0

3 years ago

1^2 + 4^2 + 7^2 -... - (3n - 2)^2 = n(6n^2 - 3n - 1)/2

Natali [406]

Answer:

−

(

−

)

(

−

)

Step-by-step explanation:

6 0

3 years ago