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3 years ago

Simplify: (–4) • (9) – (5) • (–2)

1 answer:

3 0

-4 x 9 - (-10)

= - 45 + 10
= - (45 - 10)
= - 35

Rule: Negative times positive is negative; Negative times negative is positive

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A student has a 2% salt water solution and a 7% salt water solution. To best imitate salt water at a local beach, he needs 1 lit

FromTheMoon [43]

Let

x-------> the amount of $2\%$ solution

y--------> the amount of $7\%$ solution

we know that

$2\%=0.02\\7\%=0.07\\3.5\%=0.035$

$x+y=1$

$y=1-x$ -------> equation A

$0.02x+0.07y=0.035$ -------> equation B

substitute equation A in equation B

$0.02x+0.07(1-x)=0.035$

$0.02x+0.07-0.07x=0.035$

$0.05x=0.035$

$x=0.7\ liters$

find the value of y

$y=1-x$

$y=1-0.7=0.3\ liters$

therefore

The student need $0.7\ liters$ of $2\%$ solution and $0.3\ liters$ of $7\%$ solution

the answer is

A) The percent values were written incorrectly in the equation

B) The amount of 7% solution should be written as 1 – x, not x – 1.

8 0

2 years ago

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The amount of time it takes to see a doctor a CPT-Memorial is normally distributed with a mean of 33 minutes and a standard devi

Eva8 [605]

Answer:

a) Z-score = 0.75

b) Z-score = -32.833

Step-by-step explanation:

Step(i):-

Given that mean of the Population = 33

Given a standard deviation of the Population = 12

Let 'X' be a random variable in a normal distribution

Let 'X' = 42

Step(ii):-

$Z = \frac{x-mean}{S.D}$

$Z = \frac{42-33}{12} = 0.75$

Step(iii):-

Given that mean of the Population = 89

Given a standard deviation of the Population = 1

Let 'X' be a random variable in a normal distribution

Let 'X⁻ = 82

$Z = \frac{x^{-} -mean}{\frac{S.D}{\sqrt{n} } }$

$Z = \frac{82-89}{\frac{1}{\sqrt{22} } } = -32.833$

Z-score = -32.833

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2 years ago

A principal at a large high school wants to estimate the number of days freshmen regularly ride the bus to school.

nikitadnepr [17]

Answer:

b. using a sample of size 40

Step-by-step explanation:

edg 2020

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2 years ago

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G = (5,-10),(25,-50),(50,100)

Murrr4er [49]

This is the answer not sure if you wanted it graph or not

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2 years ago

Need help an is due tomorrow and please write down why you chose that .

jolli1 [7]

The water, it is the water becuase it looks like a river.

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3 years ago

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