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monitta
2 years ago
13

After taking a 70 point test, a student guesses that he got 65 points correct. Later he finds out he got 67 points

Mathematics
1 answer:
Nataliya [291]2 years ago
4 0

Answer:

Percent error = 4.29%

Step-by-step explanation:

Percent error can be defined as a measure of the extent to which an experimental value differs from the theoretical value.

Mathematically, it is given by this expression;

Percent \; error = \frac {experimental \;value - theoretical \; value}{ theoretical \;value} *100

Given the following data;

Experimental value = 67

Theoretical value = 70

Substituting into the equation, we have;

Percent \; error = \frac {67 - 70 }{ 70} *100

Percent \; error = \frac {3}{70} *100

Percent \; error =  0.04286 *100

Percent error = 4.29%

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Multiply it by 2, add 50 & my answer is 74, what was my number
kipiarov [429]
your number was 12.

let x be the number:

(x * 2) + 50 = 74

To solve for x, we need to reverse what was done to get the answer of 74.

Since 50 was added to arrive at 74, we deduct 50 from 74.

74 - 50 = 24

We then divide 24 by 2 to get the original number.

24/2 = 12.

Your number was 12.

To check:
(12 * 2) + 50 = 74
 24 + 50 = 74
74 = 74
6 0
2 years ago
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Another math problem, i really, really need help with this one -4x^2-3+4+3-5y^2+3y^2-5y^2
VLD [36.1K]

Answer:

-4x*2 - 7y*2 + 4

Step-by-step explanation:

simplify by adding/subtracting the like terms

4 0
3 years ago
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Pam has 90 m of fencing to enclose an area in a petting zoo with two dividers to separate three types of young animals. The thre
andrew-mc [135]

Answer:

The area function is

A=\frac{135}{2}x-\frac{9}{2}x^2.

The domain and range of A is (0,15m) and (0, 253.125 m^2].

Step-by-step explanation:

The given length of fencing is 90 m.

Let the length and width of each pen be x and y respectively as shown in the figure.

As there are 3 pens, so, the total area,

A= 3 xy \;\cdots (i)

From the figure the total length of fencing is 6x+4y.

Here, for a significant area for the animals, x>0 as well as y>0 as x and y are the sides of ben.

From the given value:

6x+4y=90\;\cdots (ii)

\Rightarrow  y=\frac {45}{2}-\frac{3x}{2}

Now, from equation (i)

A=3x\left(\frac {45}{2}-\frac{3x}{2}\right)

\Rightarrow A=\frac{135}{2}x-\frac{9}{2}x^2\;\cdots (iii)

This is the required area function in the terms of variable x.

For the domain of area function, from equation (ii)

x=15-\frac{2y}{3}

\Rightarrow x [as y>0]

So, the domain of area function is (0,15m).

For the range of area function:

As x \rightarrow 0 or y\rightarrow 0, then A\rightarrow 0 [from equation (i)]

\Rightarrow A>0

Now, differentiate the area function with respect to x .

\frac {dA}{dx}=\frac{135}{2}-9x

Equate \frac {dA}{dx}  to zero to get the extremum point.

\frac {dA}{dx}=0

\Rightarrow \frac{135}{2}-9x=0

\Rightarrow x=\frac{15}{2}

Check this point by double differentiation

\frac {d^2A}{dx^2}=-9

As,  \frac {d^2A}{dx^2}, so, point x=\frac{15}{2} is corresponding to maxima.

Put this value back to equation (iii) to get the maximum value of area function. We have

A=\frac{135}{2}\times \frac {15}{2}-\frac{9}{2}\times \left(\frac {15}{2}\right)^2

\Rightarrow A=253.125 m^2

Hence, the range of area function is (0, 253.125 m^2].

4 0
3 years ago
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sertanlavr [38]
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3 years ago
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Karo-lina-s [1.5K]

Answer:

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3. -y+11

4. 7a-22

Step-by-step explanation:

Not too sure about the last one

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2 years ago
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