) Some number was added to 6.6. This sum was then divided by 0.7. Finally, the quotient was

Suppose ACT Composite scores are normally distributed with a mean of 20.6 and a standard deviation of 5.2. A university plans to

zimovet [89]

Answer:

The minimum score required for admission is 21.9.

Step-by-step explanation:

Problems of normally distributed samples are 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.

In this problem, we have that:

$\mu = 20.6, \sigma = 5.2$

A university plans to admit students whose scores are in the top 40%. What is the minimum score required for admission?

Top 40%, so at least 100-40 = 60th percentile. The 60th percentile is the value of X when Z has a pvalue of 0.6. So it is X when Z = 0.255. So

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

$0.255 = \frac{X - 20.6}{5.2}$

$X - 20.6 = 0.255*5.2$

$X = 21.9$

The minimum score required for admission is 21.9.

8 0

3 years ago

Ln(1/e^2) without calculator

castortr0y [4]

Once you remember the definition of a log, the answer to this question will literally fall out of your pencil.

First, ' Ln ' means 'natural log' ... logs to the base of ' e '.

Definition of the natural log of a number:
In order to get the number, what power do I have to raise ' e ' to ?

OK. What power do you have to raise ' e ' to in order to get 1/e² ?

Isn't 1/e² the same thing as e⁻² ?

So, in order to get 1/e² , you have to raise ' e ' to the -2 power .

In math-speak: Ln(1/e²) = <em><u>-2</u></em> .

7 0

3 years ago

Read 2 more answers

A collection of 20 coins made up of only nickels, dimes, and quarters has a total value of $3.35. If the dimes were nickels, the

Kay [80]

Answer: The required number of quarters in the collection is 11.

Step-by-step explanation: Given that a collection of 20 coins made up of only nickels, dimes and quarters has a total value of $3.35.

If the dimes were nickels, the nickels were quarters and the quarters were dimes, the collection of coins would have a total value of $2.75.

We are to find the number of quarters in the collection.

Let x, y and z represents the number of nickels, dimes and quarters respectively in the collection.

We will be using the following values of nickels, dimes and quarters in form of dollar :

1 nickel = $ 0.05, 1 dime = $ 0.10 and 1 quarter = $0.25.

Then, according to the given information, we have

$x+y+z=20\\\\\Rightarrow x=20-y-z~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)\\\\0.05x+0.10y+0.25z=3.35\\\\\Rightarrow 5x+10y+25z=335\\\\\Rightarrow x+2y+5z=67~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)\\\\0.05y+0.25x+0.10z=2.75\\\\\Rightarrow 5y+25x+10z=275\\\\\Rightarrow y+2z+5x=55~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(iii)$

Substituting the value of x from equation (i) in equations (ii) and (iii), we have

$(20-y-z)+2y+5z=67\\\\\Rightarrow y+4z=47\\\\\Rightarrow y=47-4z~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(iv)$

and

$y+2z+5(20-y-z)=55\\\\\Rightarrow -4y-3z=-45\\\\\Rightarrow y=\dfrac{45-3z}{4}~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(v)$

Comparing the values of y from equations (iv) and (v), we get

$47-4z=\dfrac{45-3z}{4}\\\\\Rightarrow 188-16z=45-3z\\\\\Rightarrow 16z-3z=188-45\\\\\Rightarrow 13z=143\\\\\Rightarrow z=\dfrac{143}{13}\\\\\Rightarrow z=11.$

Thus, the required number of quarters in the collection is 11.

7 0

3 years ago

Diana usually drives at average rate of 30 mph. If she drives for 2 hours with the speed that is 10 mph more than usual, what di

Rashid [163]

Answer: 80 miles

Step-by-step explanation:

10mph + 30mph = 40 mph

Distance = Speed × time

D = 40m/h × 2 h

D = 80 m

6 0

4 years ago

I NEED HELP ASAP WHO EVER GIVES CORRECT ANSWER GETS BRAINLEST

-BARSIC- [3]

Answer:

There will be 49 fl oz of Orange Juice and 77 fl oz in total.

Step-by-step explanation:

The ratio for Orange Juice to Sparkling Water is 7:4, so for every multiple of 4 your using of water, your using that number times 7 for Orange Juice. We are given the amount of water being used, which is 28 fl oz, so we divide that by 4 to get 7, then we multiply that by 7 for the Orange Juice and get a total of 49 fl oz of Orange Juice. The last step is to add the two totals together to get the grand total, and since we have 49 fl oz of Orange Juice and 28 fl oz or Water, we add those 2 numbers together to get 77 fl oz of Punch.

6 0

3 years ago