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Lorico [155]
3 years ago
9

Juan and Nina are in the Junior High Orchestra. As part of the orchestra they each have to learn two instruments. Juan is learni

ng to play the violin and the cello. For every 3 hours that Juan spends practicing the violin he practices the cello for 2.5 hours. Nina is learning to play the viola and cello. For every 3 hours Nina spends practicing the viola she practices the cello for 2 hours.
If Juan practiced the violin for 9 hours last week and Juan and Nina practiced the cello for the same amount of time, then Nina practiced the viola for hours last week.
Mathematics
1 answer:
stira [4]3 years ago
6 0

Answer:

Nina practiced the viola for 11.25 hours last week.

Step-by-step explanation:

Juan practiced the violin for 9 hours last week. For each 3 hours that he practices the violin, he practices 2.5 hours of cello. So

3h violin - 2.5h cello

9h violin - xh cello

3x = 9*2.5

x = 7.5

He practiced 7.5 hours of cello, the same as Nina.

For every 3 hours Nina spends practicing the viola she practices the cello for 2 hours. So:

3h viola - 2h cello

xh viola - 7.5h cello

2x = 3*7.5

x = 7.5*1.5

x = 11.25

Nina practiced the viola for 11.25 hours last week.

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A function, f(x) = 4x + 5, has a domain 0 < x < 50. What is its range?
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Answer:

f(x) = 4x+5 ; 0 ≤ x ≤ 50

 

The range is the possible output values of f(x)

 

4(0) + 5 = 5       smallest output value in range

4(50) + 5 = 55    largest output value in range

 

The outputs are between 5 and 55 including the endpoints so

the range is [5, 55]

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Nineteen more than a number is less than 42
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We are trying to find the number that when added to 19, gives us less than 42. We can set up this simple inequality:

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Now, subtract 19 from both sides:

x < 23

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3 years ago
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A cola-dispensing machine is set to dispense 8 ounces of cola per cup, with a standard deviation of 1.0 ounce. The manufacturer
pshichka [43]

Answer:

Step-by-step explanation:

Hello!

The variable of interest is X: ounces per cup dispensed by the cola-dispensing machine.

The population mean is known to be μ= 8 ounces and its standard deviation σ= 1.0 ounce. Assuming the variable has a normal distribution.

A sample of 34 cups was taken:

a. You need to calculate the Z-values corresponding to the top 5% of the distribution and the lower 5% of it. This means you have to look for both Z-values that separates two tails of 5% each from the body of the distribution:

The lower value will be:

Z_{o.o5}= -1.648

You reverse the standardization using the formula Z= \frac{X[bar]-Mu}{\frac{Sigma}{\sqrt{n} } } ~N(0;1)

-1.648= \frac{X[bar]-8}{\frac{1}{\sqrt{34} } }

X[bar]= 7.72ounces

The lower control point will be 7.72 ounces.

The upper value will be:

Z_{0.95}= 1.648

1.648= \frac{X[bar]-8}{\frac{1}{\sqrt{34} } }

X[bar]= 8.28ounces

The upper control point will be 8.82 ounces.

b. Now μ= 7.6, considering the control limits of a.

P(7.72≤X[bar]≤8.28)= P(X[bar]≤8.28)- P(X[bar]≤7.72)

P(Z≤(8.28-7.6)/(1/√34))- P(Z≤7.72-7.6)/(1/√34))

P(Z≤7.11)- P(Z≤0.70)= 1 - 0.758= 0.242

There is a 0.242 probability of the sample means being between the control limits, this means that they will be outside the limits with a probability of 1 - 0.242= 0.758, meaning that the probability of the change of population mean being detected is 0.758.

b. For this item μ= 8.7, the control limits do not change:

P(7.72≤X[bar]≤8.28)= P(X[bar]≤8.28)- P(X[bar]≤7.72)

P(Z≤(8.28-8.7)/(1/√34))- P(Z≤7.72-8.7)/(1/√34))

P(Z≤-2.45)- P(Z≤-5.71)=0.007 - 0= 0.007

There is a 0.007 probability of not detecting the mean change, which means that you can detect it with a probability of 0.993.

I hope it helps!

5 0
2 years ago
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What is the coefficient of the x^5y^5- term in the biomial expansion of (2x-3y)^10
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<u>Answer:</u>

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<u>Solution: </u>

The given expression is (2 x-3 y)^{10}

As per binomial theorem, we know,

(x+y)^{n}=\sum n C_{k} x^{n-k} y^{k}

Now here a = 2x, b = (- 3y) and n = 10 and k = 0,1,2,….10

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Now, \mathrm{T}_{6}=10 \mathrm{C}_{5} \times(2 \mathrm{x})^{(10-5)} \times(-3 \mathrm{y})^{5}=10 \mathrm{C}_{5} 2^{5} \times \mathrm{x}^{5} \times(-3)^{5} \times \mathrm{y}^{5}

So, the coefficient of x^{5} \times y^{5} \text { is }=10\left(5 \times 2^{5} \times(-3)^{5}\right.

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6 0
3 years ago
4) 16 + 7 + 9 = 7 + 9 + 16 *
nlexa [21]

Answer:

a.) Commutative Property of addition

Step-by-step explanation:

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