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3 years ago

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Tatiana had $350. she spent $180 on herself, and the rest on presents for her family. write an equation to express how much tati

ana spent on her family.

1 answer:

lara31 [8.8K]3 years ago

7 0

Answer:

$170 was spent on her family

Step-by-step explanation:

$350-$180=$170 spent on her family

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Help me plss plss I really need help I have a f

Colt1911 [192]

Answer:

A. 5 1/2 and D. 11/2

Step-by-step explanation:

Make improper fraction

8*1+3=11/8

Solve by multiplying:

4*11/8

44/8

Simplified is 11/2

We can turn it back into a mixed number

2*5+1=11 so 5 1/2

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3 years ago

142 students are going on a field trip. There will be six drivers, and two different types of vehicles. A bus can hold 51 people

otez555 [7]

Answer: 2 buses and 4 vans would be needed

Step-by-step explanation:

Let x represent the number of buses that would be needed.

Let y represent the number of vans that would be needed.

There will be six drivers, and two different types of vehicles. This means that

x + y = 6

142 students are going on a field trip. A bus can hold 51 people while a van can hold 10. This means that

51x + 10y = 142 - - - - - - - - - - - 1

Substituting x = 6 - y into equation 1, it becomes

51(6 - y) + 10y = 142

306 - 51y + 10y = 142

- 51y + 10y = 142 - 306

- 41y = - 164

y = - 164/ - 41

y = 4

x = 6 - y = 6 - 4

x = 2

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3 years ago

CaHeK987 [17]

,,......................................

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3 years ago

Which of these situations can be modeled by an exponential function?

Gwar [14]

Answer:

B) A herd of lions whose numbers triple every decade.

Step-by-step explanation:

Situations that can be modeled by exponential functions:

A situation can be modeled by exponential functions when the change is a multiplication or a division, not a sum or subtractions.

In this question:

In option A, C and D the measures are a sum or subtractions, as the rate of change is always the same. So it rests option B as the answer, as tripling is multiplying by 3.

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2 years ago

3.30 Survey response rate. Pew Research reported in 2012 that the typical response rate to their surveys is only 9%. If for a pa

Artist 52 [7]

Answer:

0% probability that at least 1,500 will agree to respond

Step-by-step explanation:

I am going to use the binomial approximation to the normal to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

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

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$n = 15000, p = 0.09$

So

$\mu = E(X) = np = 15000*0.09 = 1350$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{15000*0.09*0.91} = 35.05$

What is the probability that at least 1,500 will agree to respond

This is 1 subtracted by the pvalue of Z when X = 1500-1 = 1499. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{1499 - 1350}{35.05}$

$Z = 4.25$

$Z = 4.25$ has a pvalue of 1.

1 - 1 = 0

0% probability that at least 1,500 will agree to respond

6 0

3 years ago