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2 years ago

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

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

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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
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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

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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:

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

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Now, from equation (i)

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

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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)]

$\Rightarrow A>0$

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

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

$\frac {dA}{dx}=0$

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

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Check this point by double differentiation

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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 $(0, 253.125 m^2]$ .

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