Mac has taken seven maths exams this year. His average mark is 78%. What mark must he get on the eighth exam to raise his average to 80%?

Answers

Answer 1

Answer:

94

Step-by-step explanation:

7*78 + x = 8*80

x = 94

Or, think that he was short 2 points on each of 7 tests, so he has to make them all (14) up on the last test.


Related Questions

The price of an item yesterday was $80. Today, the price rose to $124. Find the percentage increase

Answers

Answer:

55%.

Step-by-step explanation:

1) the final percentage can be calculated if $124 is x% and 80 is 100%. Then

2)   [tex]\frac{80}{100} =\frac{124}{x}; \ = > \ x=\frac{124*5}{4}=155 \%[/tex]

3) the required increase is:

155-100=55%


[tex]sec {}^{2} a \: . \: cosec {}^{2} a = {tan}^{2}a + {cot}^{2} a + 2 \\ [/tex]
Please help!!!!!!!!!!!!​

Answers

Answer:

Trigonometric identities

[tex]\sec^2(\alpha)=1+\tan^2(\alpha)[/tex]

[tex]\csc^2(\alpha)=1+\cot^2(\alpha)[/tex]

[tex]\cot^2(\alpha)=\dfrac{1}{\tan^2(\alpha)}[/tex]

Solution

[tex]\begin{aligned}\sec^2(\alpha) \cdot \csc^2(\alpha) & = (1+\tan^2(\alpha))(1+\cot^2(\alpha))\\\\ & =1+\cot^2(\alpha)+\tan^2(\alpha)+tan^2(\alpha)\cot^2(\alpha)\\\\ & = 1+\cot^2(\alpha)+\tan^2(\alpha)+\tan^2(\alpha) \cdot \dfrac{1}{\tan^2(\alpha)}\\\\ & = 1+\cot^2(\alpha)+\tan^2(\alpha)+ \dfrac{\tan^2(\alpha)}{\tan^2(\alpha)}\\\\& = 1+\cot^2(\alpha)+\tan^2(\alpha)+1\\\\& = \tan^2(\alpha)+\cot^2(\alpha)+2\end{aligned}[/tex]

Answer:

See below ~

Step-by-step explanation:

Trigonometric Identies (needed)

sec²a = 1 + tan²a cosec²a = 1 + cot²acot²a = 1/tan²a

Solving

Expanding the LHS

sec²a * cosec²a(1 + tan²a) * (1 + cot²a)1 + tan²a + cot²a + (tan²a * cot²a)1 + tan²a + cot²a + 1tan²a + cot²a + 2⇒ RHS

∴ Hence, we have proved the left hand side of the equation is equal to the right hand side.

Solve for X
4(x + 3) = 2(x - 1)

Answers

1. Expand
4x+12=2x-2
2. Take one side away from the other
4x-2x =2x
2x+12=-2
-12
2x=-14
/2
X=-7

The circumference of the inner circle is ft. The distance between the inner circle and the outer circle is ft. By how many feet is the circumference of outer circle greater than the circumference of the inner​ circle? Use
for . PLEASE HELPPPP ASAP

Answers

Use 3.14 there’s a formula that goes with it

A sport jacket that cost the retailer$25 is marked up$10. Write as a fraction the mark up compared to the cost

Answers

Answer:

2/5

Step-by-step explanation:

markup / cost       =    10 /25 = 2/5


A tanker truck leaves a rest stop at 8:00 am traveling 50 mph.
Two hours later a flatbed truck leaves the same rest stop
traveling 60 mph. At what time will they be 85 miles apart?

o 11:30 am
o 1:30 pm
o 3:30 pm
o 10:30 am

Answers

Answer:

Step-by-step explanation:

1:30

How many people are there in row if they are numbere from 49-101? a) 51 b) 52 c) 53 d)54

Answers

53

hope it helps...!!!!

Which is the graph of f(x) = (x+3)(x-2)

Answers

Answer:

The graph of f(x) = x² was transformed to create the graph of g(x) = f(x) + 1.5. Which statement about the graphs is true?

The vertex of the graph of g is 1.5 units to the left of

the vertex of the graph of f.

B

The y-intercept of the graph of g is 1.5 units above the

y-intercept of the graph of f.

The graph of g is a reflection of the graph of f across

the y-axis.

The graph of g is a reflection of the graph of f across

the x-axis.

Step-by-step explanation:

y
10-
9
8
7
6
5
4
321
2
O
1 2 3 4 5 6 7 8 9 10
What is the gradient of the blue line?
X

Answers

Answer:

1/4

Step-by-step explanation:

Using points (0 ; 1) and (4 ; 2)

m= y2-y1 / x2-x1

= 2-1 /4-0

= 1/4

The gradient of the blue line is, 1/4

What is Equation of line?

The equation of line in point-slope form passing through the points

(x₁ , y₁) and (x₂, y₂) with slope m is defined as;

⇒ y - y₁ = m (x - x₁)

Where, m = (y₂ - y₁) / (x₂ - x₁)

Given that;

Two points on the blue line are (3, -3) and (3, -6).

Now,

Since, The equation of line passes through the points (4, 2) and (8, 3).

So, We need to find the slope of the line.

Hence, Slope of the line is,

m = (y₂ - y₁) / (x₂ - x₁)

m = (3 - 2) / (8 - 4)

m = 1 / 4

m = 1/4

Thus, The gradient of the blue line is, 1/4

Learn more about the equation of line visit:

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I genuinely need this and am giving 50 pts.

find the area of the triangle pls.
and the bottom number is a 10

options:

30.0 yd2


15.0 yd2


6.5 yd2


13.0 yd2

Answers

FromHello, Volent strawberry is here to help!

Answer: 15.0 yd2

I hope this helps!

Bye have a nice day!

From: Miko

Answer:

1. Multiply the two legs of the triangle

  3 x 10 = 30

2. Divide that number by 2

  30 / 2 = 15

The area of the triangle is 15 yd2

x-x

I WILL GIVE 21 POINTS TO THOSE WHO ANSWER THIS QUESTION RIGHT NOOOO SCAMS AND EXPLAIN WHY THAT IS THE ANSWER

Answers

Answer:

Step-by-step explanation:

the difference between any two square consecutive number is 20. find the number ?​

Answers

Answer:

hi. this is the way

Step-by-step explanation:

this is the process of doing it. hope you like it

Answer:

hey can you help me to do homework

(-2+3i)(1-2i) multiply

Answers

Answer:

The answer is

→ [tex]4 + 7i[/tex]

Step-by-step explanation:

[tex]((-2) + (3 * i)) * (1 - (2 * i)) = 4+7i[/tex]

Therefore, [tex]4+7i[/tex] is your answer.

Hope this helped! :^)

⭐Brainliest will be appreciated!⭐

✉️Message me if you have any more questions!✉️

- ✨7272033Alt

Submitted on 4/22/2022 at 12:39 PM

(To avoid plagarism, by users whom decide to copy.)

See screenshots below to prove my point that [tex]4+7i[/tex] is your answer...

solve for volume. figure out the question

Answers

Answer:

819 is the answer

Step-by-step explanation:

formula for volume is LxWxH

since volume is length * width * height, the volume for this will be 9 * 7 * 13 = 819cm^3

4. Which point is incorrectly labeled? Explain. A(0.1) B(0.5) C(0.75)​

Answers

Answer:

C

Step-by-step explanation:

It should be .7. Count each mark as .1 and this should be clear.

-11c-35/4 = 4c- 2

-11c-35 ÷4 = 4c -2

Answers

Answer:

c=-1

Step-by-step explanation:

Multiply both sides by 4

[tex]\frac{-11c-35}{4}\cdot \:4=4c\cdot \:4-2\cdot \:4[/tex]

Simplify

[tex]-11c-35=16c-8[/tex]

Add 35 to both sides

[tex]-11c-16c=16c+27-16c[/tex]

Simplify

-27c=27

Divide both sides by 27

[tex]\frac{-27c}{-27}=\frac{27}{-27}[/tex]

Simplify

c= -1

mark brainliest please!

The variance statistic is an unbiased estimator of the population variance.

O False
O True

Answers

Answer:

I think it’s false

Please help I don’t understand this

Answers

Answer:

side: 17 inchesaltitude: 6 inches

Step-by-step explanation:

The formula for the area of a triangle gives a relationship between area, height, and base length. The problem statement gives the area, and it gives another relation between height and base length. Using these two relations, you can solve for the dimensions of the triangle.

__

setup

The side to which the altitude is measured is called the "base" in the area formula. The altitude is called the "height." The relation between them given by the area formula is ...

  A = 1/2bh

  51 = 1/2bh . . . . . . using the given value for area

The other relation given by the problem statement is that the base is 1 less than 3 times the height:

  b = 3h -1 . . . . . . . base is 1 less than 3 times altitude

__

solution

Using this second equation to substitute for 'b' in the first equation, we have ...

  51 = 1/2(3h -1)h

  102 = 3h² -h . . . . multiply by 2, eliminate parentheses

  3h² -h -102 = 0 . . . . . put in standard form

  3h² -18h +17h -102 = 0 . . . . . prepare to factor

  3h(h -6) +17(h -6) = 0 . . . . . factor pairs of terms

  (3h +17)(h -6) = 0 . . . . . . . . finish factoring

Solutions are the values of h that make these factors zero:

  3h +17 = 0   ⇒   h = -17/3

  h -6 = 0   ⇒   h = 6

We know that dimensions in a geometry problem must be positive, so the solution here is h = 6. Then b = 3h -1 = 3(6) -1 = 17. The dimensions are all in inches.

The length of the side is 17 inches; the altitude to that side is 6 inches.

The radius of a circle is 9 feet. What is the Area and the circumference of the circle?

Answers

Answer:

area is 254.34 circumference is 56.52

Step-by-step explanation:

To find the area you need to follow the formula r^2(pi)

so it would be 9x9x3.14 which is 254.34

to find circumference you need to find diameter which is double the radius (9x2) so the diameter is 18

To find circumference to need to do radius x pi

18x3.14 is 56.52

I WILL GIVE 20 POINTS TO THOSE WHO ANSWER THIS QUESTION RIGHT NOOOO SCAMS PLEASE AND PLEASE EXPLAIN WHY THAT IS THE ANSWER

Answers

Answer: 5x 5y

Step-by-step explanation: because of the length

What is the area of this figure?

Composite figure composed of a square with dimensions 3 ft by 3 ft, triangle with a base of 11 ft and a height of 3 ft and rectangle with dimensions 11 ft by 3 ft.

Answers

The area of the composite figure = area of square + area of triangle + area of rectangle = 58.5 ft²

What is the Area of the Composite Figure?

Area of the composite figure = area of square + area of triangle + area of rectangle = s² + 1/2(bh) + lw

Given the following:

s = 3 ftb = 11 fth = 3 ftl = 11 ftw = 3 ft

Area of the composite figure = (3²) + 1/2(11)(3) + (11)(3)

Area of the composite figure = 58.5 ft²

Learn more about the area of a composite figure on:

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(4√7 + √3) (√7 - 2√3)
Solve by multiplying and simplifying radical expression

Answers

22-7 (square root)21. or -10.8

Evaluate the function.

f(x) = -x^2+3

Find f(-2)

Answers

Answer:

Step-by-step explanation:

f(x)= -(-2)^2 + 3 = -4 + 3 = -1

Write the formula that shows the dependence of:
HELP PLEASE

Answers

[tex]\qquad\qquad\huge\underline{{\sf Answer}}[/tex]

[tex] \textbf{Volume of a cube can be represented as :} [/tex]

[tex] \textsf{ side³} [/tex]

[tex] \textsf{And the side length is given as a} [/tex]

[tex] \textsf{So, volume of the given cube is :} [/tex]

[tex] \textsf{V = a³ } [/tex]

If a right angle triangle has a hypotenuse of length 13 units and a leg of length 7 units, what would
be the length of the other leg?



OA) 13 units
OB) √120 units
OC) 7 units
OD) √102 units

Answers

Answer:

the square root of 120

Step-by-step explanation:

a^2+b^2=c^2

a^2+7^2=13^2

a^2+49=169

a^2=120

a= the square root of 120

Find three positive numbers the sum of which is 27, such that the sum of their squares is as small as possible.

Answers

The three positive numbers whose sum is 27 will be 14, 1, and 12.

What is the number?

A number is a mathematical entity that can be used to count, measure, or name things. For example, 1, 2, 56, etc. are the numbers.

Suppose the three positive numbers are x, y and z.

If the summation of numbers is 27.

⇒ x + y + z = 27 --- (1)

⇒ z = 27 - x - y

Suppose the square sum of the number be S.

∴ S = x² + y² + z²

⇒ S = x²+ y² + (27 - x - y)² --- (2)

We will optimize the function, partially differentiating it with respect to x and y, and setting dS/dx = 0 to get the minimum value of S.

2x + 2(27- x - y)(-1) = 0

2x - 54 + 2x + 2y = 0

4x + 2y - 54 = 0

y = 27 - 2x --- (3)

Differentiate partially with respect to y as

2y + 2(27 - x - y)(-1) = 0

2y - 54 + 2x + 2y = 0

4y + 2x - 54 = 0

x = 54 - 2y --- (4)

Substitute the value of y = 27 - 2x in the equation (4),

x = 12 - 2(27 - 2x)

x = 12 - 54 + 4x

4x - x = 54 - 12

3x = 42

⇒ x = 14

By substituting x = 14 in equation (3)

y =2(14) - 27

y = 28 - 27

⇒ y = 1

Substitute the values of x and y in equation (1),

14 + (1) + z = 27

z = -14+27-1

z= 12

Thus, the three positive numbers whose sum is 27 will be 14, 1, and 12.

Learn more about the number here:

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PLEASE HELP ME ASAP IM LOSING POINTS

Answers

Let's solve this problem step-by-step:

      1. Let's put this in a fraction format:  

             6834 ÷ 17 = [tex]\frac{6834}{17}[/tex]

      2. Now we know 6834 = 6800 + 34

            ⇒ so:

                   [tex]\frac{6834}{17} =\frac{6800+34}{17} =\frac{6800}{17} +\frac{34}{17}[/tex]

     3. Now let's convert the fractions to denominators

              [tex]\frac{6800}{17} +\frac{34}{17} =[/tex] (6800 ÷ 17) + (34 ÷ 17)    

Let's check:

6834 ÷ 17 = 402(6800 ÷ 17) + (34 ÷ 17) = (400) + (2) = 400 + 2 = 402

         

Answer:  (6800 ÷ 17) + (34 ÷ 17) or Choice (C)

Mrs little and jack go on a hike. After 2 hours, they have gone 300 feet. After 6 hours, they have gone 800 feet. What is the average rate of change?

Answers

Answer:

125 ft/hr

Step-by-step explanation:

dx/dt = (800-300)/(6-2) = 500/4 = 125

3x+8=2x+7

What the anwser pls solve em out

Answers

Answer: hii

Your answer is  x= −1

Step-by-step explanation:

Solve for x by simplifying both sides of the equation, then isolating the variable.

Hopefully this helps you

- Matthew

Find the length of side and the perimeter of a regular nine sided polygon with radius 5 units

Answers

Step-by-step explanation:

Nine sided polygon has an angle of 360/9=40 degrees at one vertex.

So the angles opposite the radius=(180–40)/2==140/2=70degrees.

solving for Base(side): 1/2s=5.cos70= 3.42 units Ans

P=9(5+3.42)=75.78 units Ans.

I search it. ‍♀️

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