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Anika [276]
3 years ago
7

This is all I know what to do any help?

Mathematics
1 answer:
svetoff [14.1K]3 years ago
4 0
You can multiply the second equation by -2 

-5x + y = 15         everything by -2

10x - 2y = -30

now you can solve them

2x + 2y = -6
10x - 2y = -30

y cancels

2x= -6
10x = -30


12x = -36
/12.     /12

x = -3 


now to solve for y you substitute x for -3

-5(-3) + y = 15
15 + y = 15 
-15        -15

       y= 0
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At the candy shop, Ameenah sells chocolate covered raisins, c, for $1.50 per pound, and peanuts, p, for $1.20 per pound. Ameenah
insens350 [35]

Answer:

10 pounds of raisins and 10 pounds of peanuts.

Step-by-step explanation:

Let c represent the pounds of chocolate covered raisins.

Let p represent the pounds of peanuts.

We know that the raisins cost $1.50 per pound and the peanuts cost $1.20 per pound.

Ameenah wants to make 20 pounds of a mixture of the raisins and peanuts that sells for 1.35 a pound. So, we can write the following expression:

1.5c+1.2p

This represents the cost given c pounds of raisins and p pounds of peanuts.

Ameenah wants to combine c and p to make them 1.35 per pound. In other words, the expression must equal:

1.5c+1.2p=1.35(c+p)

We also know that she wants to make 20 pounds. So, c plus p must total 20. Therefore:

c+p=20

We now have the system of equations:

\left\{ \begin{array}{ll} 1.5c+1.2p=1.35(c+p) \\ c+p=20\end{array}

First, since we know that c+p is 20, we can substitute that into the first equation.

Second, let's subtract p from both side for the second equation to isolate a variable. So:

c=20-p

Let's now substitute this into the first equation:

1.5(20-p)+1.2p=1.35(20)

Distribute:

30-1.5p+1.2p=27

Combine like terms:

-0.3p+30=27

Subtract 30 from both sides:

-0.3p=-3

Divide both sides by -0.3. So, the amount of peanuts needed is:

p=10

10 pounds of peanuts is needed.

This means that 20-10 or 10 pounds of raisins is needed.

5 0
3 years ago
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Complete Question

The complete question is shown on the first uploaded image

Answer:

a

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b

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c

 The correct option is  D

Step-by-step explanation:

From the question we are told that

    The margin of error is   E  =  0.23

     The largest value is  k =  15

     The smallest value is  u = 7

From the question we are told the confidence level is  95% , hence the level of significance is    

      \alpha = (100 - 95 ) \%

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Generally from the normal distribution table the critical value  of  \frac{\alpha }{2} is  

   Z_{\frac{\alpha }{2} } =  1.96

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      \sigma  =  \frac{Range }{4}

Here the Range is mathematically represented as

       Range  =  k - u

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=>    Range  = 8

=>   \sigma  =  \frac{8 }{4}

=>   \sigma  =  2

Generally the sample size is mathematically represented as

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=>   n = [1.96  *  2 }{0.23} ] ^2

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Generally to obtain a  conservatively small sample size the population standard deviation estimate becomes

=>   \sigma  =  \frac{Range }{6}

=>   \sigma  =  \frac{8 }{6}

=>   \sigma  =1.333

Generally the conservatively small sample size is mathematically evaluated as

n = [\frac{Z_{\frac{\alpha }{2} } *  \sigma }{E} ] ^2

=>   n = [1.96  *  1.333 }{0.23} ] ^2

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Answer:

≈ 11.78 in

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The slope is -1/4. Hope this helps! Please mark brainliest! Thank you v much! :)

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