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alexandr1967 [171]

4 years ago

12

An Arithmetic series has 20 terms. The first term is -81. The sum of all the terms is -480. Use the arithmetic sum formula to fi

nd the last term

1 answer:

timama [110]4 years ago

4 0

Answer:

The last term is 33.

Step-by-step explanation:

Sn = (n/2)(a1 + L) where a1 = first term and L = the last.

So:

-480 = (20/2) ( -81 + L)

-480 = 10( L - 81)

L- 81 = -480 / 10 = -48

L = -48 + 81

L = 33.

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Find the value of x.

zimovet [89]

Answer:

x = 30

Step-by-step explanation:

We know that the angle is a right angle, which is equal to 90. So in order to see what the equation is equal to, we have to subtract 81 from 90.

90 - 81 = 9

With the answer we get, we can now begin to solve for x.

2x - 51 = 9, add 51 to both sides

2x = 60, divide 60 by 2 to get x

x = 30

Now, to check your work, plug 30 into the equation.

2(30) - 51

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3 years ago

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Which equation represents a proportional relationship that has a constant of proportionality equal to -10?

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Step-by-step explanation:

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3 years ago

There are 10 marbles in a bag. Four are blue, 3 are black and 2 white and 1 red. If the marbles are not replaced once they are d

stich3 [128]

<u>Given</u>:

Given that there are 10 marbles in a bag. 4 are blue, 3 are black, 2 are white and 1 is red.

The marbles are selected by not replacing the drawn ones.

We need to the probability of selected a black marble and then a white marble without replacement.

<u>Probability</u>:

Let B denote the black marble.

Let W denote the white marble.

The probability of selecting a black marble is $P(B)=\frac{3}{10}$

The probability of selecting a white marble without replacement is $P(W)=\frac{2}{9}$

The probability of selecting a black marble and then a white marble without replacement is given by

$P(B \ and \ W)=P(B) \cdot P(W)$

Substituting the values, we get;

$P(B \ and \ W)=\frac{3}{10} \cdot \frac{2}{9}$

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$P(B \ and \ W)=\frac{1}{15}$

Thus, the probability of selecting a black marble and then a white marble without replacement is $\frac{1}{15}$

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3 years ago

A study is conducted to test the hypothesis that people with glaucoma have higher than average blood pressure. The study include

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Answer: The confidence interval would be (120.6, 159.4).

Step-by-step explanation:

Since we have given that

n = 200

mean = $\bar{x}=140\ mm$

Standard deviation = $\sigma=25\ mm$

At 95% confidence interval, z = 1.96

So, 95% confidence interval would be

$\bar{x}\pm z\dfrac{\sigma}{\sqrt{n}}\\\\=140\pm 1.96\times \dfrac{140}{\sqrt{200}}\\\\=140\pm 19.40\\\\=(140-19.4,140+19.4)\\\\=(120.6,159.4)$

Hence, the confidence interval would be (120.6, 159.4).

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4 years ago

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Answer:

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Step-by-step explanation:

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3 years ago