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vivado [14]
3 years ago
9

HELP ASAP! PLS!! The Water Department checks the city water supply on a regular basis for

Mathematics
2 answers:
aleksandr82 [10.1K]3 years ago
8 0

Answer:

B. 95% confident the average concentration of PCBs in the water supply is between 2.9 ppb and 3.5 ppb

Step-by-step explanation:

You are given the total number of samples, the concentration of lead, and the standard deviation. The standard deviation represents how inaccurate the estimation of the concentration of lead in the drinking water. This means that there can only possibly be a 0.3 ppb error in the estimation. 3.2-0.3=2.9, and 3.2+0.3=3.5

Mazyrski [523]3 years ago
7 0

Answer:

99.7% confident the average concentration of PCBs in the water supply is between 2.3 parts per billion and 4.1 parts per billion.

Step-by-step explanation:

Just took the question, this is the correct answer.

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Can someone please help this is due at 9
likoan [24]

Answer:

70

Step-by-step explanation:

We have the final part 4x/40 = 7. We can simplify this to x/10 = 7 by dividing the numerator and the denominator by 4. We then multiply both sides by 10 to get x = 70

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A toy train makes 10 laps around a track in 12 minutes. hpw me my laps per hour is that.
marusya05 [52]

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50

Step-by-step explanation:


3 0
3 years ago
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When factoring the equation 9x2+9x+2 what two numbers will the "9x" term be broken into?
Andrew [12]

Answer:

it will be broken into 9*what ever x is

Hope This Helps!!!

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3 years ago
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3. if kx² + 2x + k = -kx have equal roots, find the values of k.<br>​
crimeas [40]

Answer:

k = - \frac{2}{3} , k = 2

Step-by-step explanation:

Using the discriminant Δ = b² - 4ac

The condition for equal roots is b² - 4ac = 0

Given

kx² + 2x + k = - kx ( add kx to both sides )

kx² + 2x + kx + k = 0 , that is

kx² + (2 + k)x + k = 0 ← in standard form

with a = k, b = 2 + k and c = k , thus

(2 + k)² - 4k² = 0 ← expand and simplify left side

4 + 4k + k² - 4k² = 0

- 3k² + 4k + 4 = 0 ( multiply through by - 1 )

3k² - 4k - 4 = 0 ← in standard form

(3k + 2)(k - 2) = 0 ← in factored form

Equate each factor to zero and solve for k

3k + 2 = 0 ⇒ 3k = - 2 ⇒ k = - \frac{2}{3}

k - 2 = 0 ⇒ k = 2

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4 years ago
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The answer is 51 first u multiply and divide then calculate
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