Hi I need help what is 15 divided by 156

Deanna gets 3 problems incorrect on her math quiz and scores 85%. How many questions were on the quiz?

katrin2010 [14]

Answer:

There were 20 questions on the quiz

Step-by-step explanation:

In this question, we are concerned with knowing the number of questions on a quiz, given that Deana had a certain percentage after scoring an amount of marks.

We proceed as follows;

Let the number of questions on the quiz be X.

Now, she got 85% by making 3 incorrect choices. This means the percentage of questions she got incorrectly would be 100-85 = 15%

what we are saying is that it is just 15% of her questions that were wrong.

This mathematically;

15% of x = 3

15/100 * x = 3

15x = 3 * 100

15x = 300

x = 300/15

x = 20

5 0

3 years ago

For a rectangle with length of

AveGali [126]

Answer:

2x+5

Step-by-step explanation:

Formula for the perimeter of a reactangle= 2(l+b)

So,

2(l+b) = 10x+18

2(3x+4 + b) = 10x+18

Rearrange and solve

3x+4+b = 5x+9

b = 5x+9 - 3x - 4

b = 2x+5

Thus the measurement of the width = 2x+5

Hope this helps

6 0

3 years ago

During a musical an orchestra is playing. As the music plays, the volume changes in the beginning of the piece can be modeled by

noname [10]

Answer:

Kindly check explanation

Step-by-step explanation:

Given the model:

s = 10│x - 4│+ 50

s represents the sound level in decibels and x represents the number of measures of music played

To find x at s = 80

The equation becomes /

80 = 10│x - 4│+ 50

Subtract 50 from both sides of the equation

80 - 50 = 10 |x - 4| + 50 - 50

30 = 10 | x - 4 |

Divide both sides by 10

30/10 = 10|x - 4| / 10

3 = |x - 4|

|x - 4| is an absolute value expression

±3 = |x - 4|

x = 3 + 4 = 7

x = - 3 + 4 = 1

4 0

3 years ago

Find the length to the nearest centimeter of the diagonal of a square 30 cm. on a side

tiny-mole [99]

Answer:

42 cm.

Step-by-step explanation:

Please find the attachment.

Let x be the length of diagonal of the square.

We have been given that length of each side of a square is 30 cm. We are asked to find the length of the diagonal of square to the nearest centimeter.

We can see from our diagram that triangle AC is the diagonal of our square.

Since all the interior angles of a square are right angles or equal to 90 degrees, so we will use Pythagoras theorem to find the length of diagonal.

$AC^2=AD^2+DC^2$

Upon substituting our given values in above formula we will get,

$x^2=(30\text{ cm})^2+(30\text{ cm})^2$

$x^2=900\text{ cm}^2+900\text{ cm}^2$

$x^2=1800\text{ cm}^2$

Let us take square root of both sides of our equation.

$x=\sqrt{1800\text{ cm}^2}$

$x=42.4264\text{ cm}\approx 42\text{ cm}$

Therefore, the length of diagonal of our given square is 42 cm.

8 0

3 years ago

can anyone help me with these? I'm having a lot of trouble and I'm extremely behind... I need to catch up badly!!! i have been a

TiliK225 [7]

Answer:

Step-by-step explanation:

5 and 6 are the same, so I will do one of those and you can use the example to do the other one.

Slope-intercept form is y = mx + b. If we have 2 points and nothing else, we can use those 2 points in the slope formula to find the slope (the m value in the equation) and then plug that in with either one of the points to get the equation. The slope formula is:

$m=\frac{y_{2} -y_{1} }{x_{2}-x_{1} }$

Using our points in question 5: (2, 4) (5, 4)

$m=\frac{4-4}{5-2} =\frac{0}{3}=0$ So m = 0. Now pick a point and use it in the equation along with the m value to solve for b. I will use (2, 4):

4 = 0(2)+b and

4 = 0 + b so

b = 4.

Now we have m = 0 and b = 4 so we fill in the equation with that info:

y = 0x + 4 or simplifying,

y = 4

For question 7 they want the line parallel to y = 3x + 6 that goes through (-10, 2.5). For a line to be parallel to another line, their slopes have to be identical. The slope in y = 3x + 6 is 3. So the slope of the "new" line is going to be 3 as well. Now we will use that slope and the given point to solve for b, just like in #5:

2.5 = 3(-10) + b and

2.5 = -30 + b so

b = 32.5

Now we will fill in:

y = 3x + 32.5

For question 8 they want the line perpendicular to y = -4x - 2 that goes through (-16, -11). For a line to be perpendicular to another line, their slopes have to be opposite reciprocals. Opposite meaning the sign is opposite (positive becomes negative and negative becomes positive), and reciprocal meaning the fraction is flipped upside down. The slope in our line is -4. That means that the perpendicular slope is positive 1/4. Using that along with our point, we will again solve for b:

$-11=\frac{1}{4}(-16)+b$ which simplifies to

-11 = -4 + b so

b = -7

Now we fill in:

$y=\frac{1}{4}x-7$

For question 8, in order to find the line parallel to the given line, you need to know the slope. In the form it is currently in, we do not know the slope. We need to put it into slope-intercept form to find the slope, then we will proceeed as above. If

x + 4y = 6, then

4y = -x + 6 and, dividing by 4,

$y=-\frac{1}{4}x+\frac{3}{2}$