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2 years ago

PLEASE HELP I really need Help Im offering 100 Points so please help me

Mathematics

2 answers:

Vlada [557]2 years ago

8 0

Answer:

i guess it's D

Step-by-step explanation:

garik1379 [7]2 years ago

6 0

Answer:

Step-by-step explanation:

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John runs to the market and comes back in 15 minutes. His speed on the way to the market is 5m/s and his speed on the way back i

katen-ka-za [31]

Answer:

The distance to the market is 2000 m

Step-by-step explanation:

∵ John runs to the market and comes back in 15 minutes

→ Change the min. to the sec. because the unit of his speed is m/s

∵ 1 minute = 60 seconds

∴ 15 minutes = 15 × 60 = 900 seconds

→ Assume that t1 is his time to the market and t2 is his time from

the market

∵ t1 + t2 = 15 minutes

∴ t1 + t2 = 900 ⇒ (1)

→ Assume that the distance to the market is d

∵ His speed on the way to the market is 5m/s

∵ Time = Distance ÷ Speed

∴ t1 = d ÷ 5 ⇒ (1 ÷ 5 = 0.2)

∴ t1 = 0.2d ⇒ (2)

∵ His speed on the way back is 4m/s

∴ t2 = d ÷ 4 ⇒ (1 ÷ 4 = 0.25)

∴ t2 = 0.25d ⇒ (3)

→ Substitute (2) and (3) in (1)

∵ 0.2d + 0.25d = 900

∴ 0.45d = 900

→ Divide both sides by 0.45

∴ d = 2000 m

∴ The distance to the market = 2000 m

8 0

3 years ago

WILL GIVE BRAINLIEST In a survey of 2,800 people who owned a certain type of car, 700 said they would buy that type of car agai

nirvana33 [79]

Answer:

25% of people said that they were satisfied.

Step-by-step explanation:

700 x 4 = 2,800 which means 700 is 1/4 of 2,800 and 1/4 as a percentage is 25%

5 0

3 years ago

Read 2 more answers

Maricell, the fruit juggler, bought 0.24 pounds of apples and 3.1 pounds of oranges. How many pounds of fruit did Maricell buy?

frosja888 [35]

The answer is 3.34 pounds also the estimate would be 3 pounds.

3 0

3 years ago

the sum of three numbers is 128.The third number is 10 more than the first .The second number 4 times the third number. what are

Ray Of Light [21]

128 = a + + 4(a + 10) + (a + 10)
128 = a + 4a + 40 + a + 10
128 = 6a + 50
128-50 = 6a
78 = 6a
13 = a

1st = a = 13
2nd = 4(a + 10) = 4(23) = 92
3rd = a + 10 = 23

3 0

3 years ago

A practice law exam has 100 questions, each with 5 possible choices. A student took the exam and received 13 out of 100.If the s

Cloud [144]

Answer:

$z=\frac{13-20}{4}=-1.75$

Assuming:

H0: $\mu \geq 20$

H1: $\mu$

$p_v = P(Z$

Step-by-step explanation:

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Let X the random variable of interest (number of correct answers in the test), on this case we now that:

$X \sim Binom(n=100, p=0.2)$

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 need to check the conditions in order to use the normal approximation.

$np=100*0.2=20 \geq 10$

$n(1-p)=20*(1-0.2)=16 \geq 10$

So we see that we satisfy the conditions and then we can apply the approximation.

If we appply the approximation the new mean and standard deviation are:

$E(X)=np=100*0.2=20$

$\sigma=\sqrt{np(1-p)}=\sqrt{100*0.2(1-0.2)}=4$

So we can approximate the random variable X like this:

$X\sim N(\mu =20, \sigma=4)$

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean". The letter $\phi(b)$ is used to denote the cumulative area for a b quantile on the normal standard distribution, or in other words: $\phi(b)=P(z$