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oksano4ka [1.4K]
2 years ago
6

Suppose you have 20 coins that total $3.00. Some coins are nickels and some are quarters. Which of the following pairs of equati

ons would you use to find out how many of each coin you have?
Mathematics
1 answer:
kap26 [50]2 years ago
5 0

Answer:

Step-by-step explanation:

n + q = 20

.05n + .25q = 3.00

5n + 25q = 300

 n + q = 20

5n + 25q = 300

-5n - 5q = -100

20q = 200

q = 10 quarters

n + 10 = 20

n = 10 nickels

(10 nickels, 10 quarters)

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0.075km, 7.6m, 77cm, 780mm from smallest to largest
Neko [114]

Answer:

77cm, 780mm, 7.6m, 0.075km

this is the best answer

7 0
2 years ago
A committee of 15 members is voting on a proposal. Each member casts a yea or nay vote. On a random voting basis, what is the pr
Igoryamba

Answer:

0.006% probability that the final vote count is unanimous.

Step-by-step explanation:

For each person, there are only two possible outcomes. Either they vote yes, or they vote no. The probability of a person voting yes or no is independent of any other person. So we use the binomial probability distribution 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.

Random voting:

So 50% of voting yes, 50% no, so p = 0.5

15 members:

This means that n = 15

What is the probability that the final vote count is unanimous?

Either all vote no(P(X = 0)) or all vote yes(P(X = 15)). So

p = P(X = 0) + P(X = 15)

In which

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

P(X = 0) = C_{15,0}.(0.5)^{0}.(0.5)^{15} = 0.00003

P(X = 15) = C_{15,15}.(0.5)^{15}.(0.5)^{0} = 0.00003

So

p = P(X = 0) + P(X = 15) = 0.00003 + 0.00003 = 0.00006

0.006% probability that the final vote count is unanimous.

7 0
1 year ago
Which statements are true regarding the transformation? Check all that apply. EF corresponds to E'F'. FG corresponds to G'D'. ∠E
8090 [49]

Answer: A,C,D,F

Step-by-step explanation:

3 0
2 years ago
Read 2 more answers
Suppose Johnny invests $41,745 into an account, which has been earning interest for many years and he now has a total of $39,974
Tcecarenko [31]
The interest means the amount that adds up to your previous capital that you invest in the past. If you invest an amount of money and get an interest revenue out of it, the amount of your capital will be increased, not decreased.
7 0
2 years ago
In a study of hormone supplementation to enable oocyte retrieval for assisted reproduction, a team of researchers administered t
olchik [2.2K]

Answer:

Note: This question is incomplete and complete question is posted down below with multiple choice questions and from Option 3 is correct

Step-by-step explanation:

Note: This question is incomplete and it is a multiple choice question. With the following multiple choices to select from.

1. The researchers expect that 80% of all similarly constructed intervals will contain the true mean number of oocytes that could be retrieved from the population of women aged 36-40 years.

2. The researchers expect that 80% of all similarly constructed intervals will contain the mean number of oocytes retrieved in the sample of 98 women aged 36-40 years.

3. There is a 80% chance that the the true mean number of oocytes that could be retrieved from the population of women aged 36-40 years is uniquely contained in the reported interval.

4. The researchers expect that 80% of all similarly constructed intervals will contain the range of the number of oocytes that could be retrieved from the population of women aged 36-40 years.

we have to select the appropriate answer from the above options.  

So, in order to choose the correct option, first we need to understand the confidence interval.

Confidence Interval is a range of value for which are pretty sure our true values will lie in that interval. For example, in this question, we have 80% confidence interval and it means there is a 80% confident chance that our true values will lie in that 80% interval. Let's calculate it.

We have following data given from the question.    

Sample = 98

Mean = 9.7

Confidence Interval = 80%

Z = 1.282

And formula for confidence interval is :

Mean ± Z x SD/\sqrt{n}

For this equation, we have all quantities except SD which is standard deviation. Let's calculate it first.

Standard deviation is square root of variance and so we need to calculate variance first.

Mean = Sum/ total number

9.7 = Sum/ 98

Sum = 950.6

For variance we will use this sum.

s² = (950.6 (1 - 9.7)²) ÷ (98-1)

s² = 741. 762 = Variance.

Let's calculate Standard deviation

SD = \sqrt{variance}

SD = \sqrt{741.762}

SD = 27.23 = Standard Deviation.

Now, we have complete data to calculate range of values for the confidence interval of 80%

Mean ± Z x SD/\sqrt{n}

Here, Z is the Z-score and it has predetermined value for different confidence intervals and here in our case for 80% , Value of Z = 1.282

Now, by just plugging in the values in to above formula we will get range of values or confidence interval of 80% in which our true value will likely to lie.

9.7 ± 1.282 x 27.23/\sqrt{98}

9.7 ± 3.52 Or

9.7 + 3.52 = 13.22

9.7 - 3.52 = 6.18

Rangle of Values with confidence interval of 80% = (6.18 to 13.22).

Which means that, our true mean will most likely lie in this interval.

So, the option 3 is correct which meets the correct definition and interpretation of the problem.  

6 0
2 years ago
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