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Alexxandr [17]
2 years ago
9

6 The bar chart shows the A-level mathematics grades achieved by some students one year. A-level grades 120 100- 80 Frequency 60

40 20 om 0 A* A B D E U С Grade a How many students achieved grade B or C? b How many students took A-level mathematics? c Estimate the probability that a student will achieve grade B or C next year.​
Mathematics
1 answer:
skelet666 [1.2K]2 years ago
5 0

Answer:

very hard very hard

Step-by-step explanation:

other will answer it

You might be interested in
What is the solution set of (x-2)(x-3)=3
natali 33 [55]

Answer:

x =(5-√13)/2= 0.697

x =(5+√13)/2= 4.303

Step-by-step explanation:

Step  1  :

Equation at the end of step  1  :

 (x - 2) • (x - 3) -  3  = 0  

Step  2  :

Trying to factor by splitting the middle term

2.1     Factoring  x2-5x+3  

The first term is,  x2  its coefficient is  1 .

The middle term is,  -5x  its coefficient is  -5 .

The last term, "the constant", is  +3  

Step-1 : Multiply the coefficient of the first term by the constant   1 • 3 = 3  

Step-2 : Find two factors of  3  whose sum equals the coefficient of the middle term, which is   -5 .

     -3    +    -1    =    -4  

     -1    +    -3    =    -4  

     1    +    3    =    4  

     3    +    1    =    4  

Observation : No two such factors can be found !!

Conclusion : Trinomial can not be factored

Equation at the end of step  2  :

 x2 - 5x + 3  = 0  

Step  3  :

Parabola, Finding the Vertex :

3.1      Find the Vertex of   y = x2-5x+3

Parabolas have a highest or a lowest point called the Vertex .   Our parabola opens up and accordingly has a lowest point (AKA absolute minimum) .   We know this even before plotting  "y"  because the coefficient of the first term, 1 , is positive (greater than zero).  

Each parabola has a vertical line of symmetry that passes through its vertex. Because of this symmetry, the line of symmetry would, for example, pass through the midpoint of the two  x -intercepts (roots or solutions) of the parabola. That is, if the parabola has indeed two real solutions.  

Parabolas can model many real life situations, such as the height above ground, of an object thrown upward, after some period of time. The vertex of the parabola can provide us with information, such as the maximum height that object, thrown upwards, can reach. For this reason we want to be able to find the coordinates of the vertex.  

For any parabola,Ax2+Bx+C,the  x -coordinate of the vertex is given by  -B/(2A) . In our case the  x  coordinate is   2.5000  

Plugging into the parabola formula   2.5000  for  x  we can calculate the  y -coordinate :  

 y = 1.0 * 2.50 * 2.50 - 5.0 * 2.50 + 3.0

or   y = -3.250

Parabola, Graphing Vertex and X-Intercepts :

Root plot for :  y = x2-5x+3

Axis of Symmetry (dashed)  {x}={ 2.50}  

Vertex at  {x,y} = { 2.50,-3.25}  

x -Intercepts (Roots) :

Root 1 at  {x,y} = { 0.70, 0.00}  

Root 2 at  {x,y} = { 4.30, 0.00}  

Solve Quadratic Equation by Completing The Square

3.2     Solving   x2-5x+3 = 0 by Completing The Square .

Subtract  3  from both side of the equation :

  x2-5x = -3

Now the clever bit: Take the coefficient of  x , which is  5 , divide by two, giving  5/2 , and finally square it giving  25/4  

Add  25/4  to both sides of the equation :

 On the right hand side we have :

  -3  +  25/4    or,  (-3/1)+(25/4)  

 The common denominator of the two fractions is  4   Adding  (-12/4)+(25/4)  gives  13/4  

 So adding to both sides we finally get :

  x2-5x+(25/4) = 13/4

Adding  25/4  has completed the left hand side into a perfect square :

  x2-5x+(25/4)  =

  (x-(5/2)) • (x-(5/2))  =

 (x-(5/2))2

Things which are equal to the same thing are also equal to one another. Since

  x2-5x+(25/4) = 13/4 and

  x2-5x+(25/4) = (x-(5/2))2

then, according to the law of transitivity,

  (x-(5/2))2 = 13/4

We'll refer to this Equation as  Eq. #3.2.1  

The Square Root Principle says that When two things are equal, their square roots are equal.

Note that the square root of

  (x-(5/2))2   is

  (x-(5/2))2/2 =

 (x-(5/2))1 =

  x-(5/2)

Now, applying the Square Root Principle to  Eq. #3.2.1  we get:

  x-(5/2) = √ 13/4

Add  5/2  to both sides to obtain:

  x = 5/2 + √ 13/4

Since a square root has two values, one positive and the other negative

  x2 - 5x + 3 = 0

  has two solutions:

 x = 5/2 + √ 13/4

  or

 x = 5/2 - √ 13/4

Note that  √ 13/4 can be written as

 √ 13  / √ 4   which is √ 13  / 2

Solve Quadratic Equation using the Quadratic Formula

3.3     Solving    x2-5x+3 = 0 by the Quadratic Formula .

According to the Quadratic Formula,  x  , the solution for   Ax2+Bx+C  = 0  , where  A, B  and  C  are numbers, often called coefficients, is given by :

                                     

           - B  ±  √ B2-4AC

 x =   ————————

                     2A

 In our case,  A   =     1

                     B   =    -5

                     C   =   3

Accordingly,  B2  -  4AC   =

                    25 - 12 =

                    13

Applying the quadratic formula :

              5 ± √ 13

  x  =    —————

                   2

 √ 13   , rounded to 4 decimal digits, is   3.6056

So now we are looking at:

          x  =  ( 5 ±  3.606 ) / 2

Two real solutions:

x =(5+√13)/2= 4.303

or:

x =(5-√13)/2= 0.697

4 0
3 years ago
Read 2 more answers
Need help ASAP! Show work if you can, it’s fine if not tho!
Elza [17]

Answer:

Step-by-step explanation:

(2(6) - 3(10)^2)/(|6 - 10)|

(12 - 300)/|-4|

-288/4 = -72

answer is c

3 0
3 years ago
Read 2 more answers
I need help i dont understand this​
mel-nik [20]
140 tickets sold at the door

Step by Step Explanation:

x = tickets sold in advance
y = tickets sold at the door

We use the formula ax+by=c and a+b=c

x + y = 514
17x + 20y = 9158

y = 514 - x
17x + 20(514 - x)
17x + 10,280 - 20x = 9,158
-3x + 10,280 = 9,158
-3x = -11222
x = 374

This is for tickets sold in advance so we need to find y

374 + y = 514
y = 140

140 tickets were sold at the door

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The price of gasoline was 96¢ a gallon<br> before it went up 25%. How much did<br> it go up?
maria [59]
It went up 24c because 25% of 96c is 24c
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If the purchase price for a house is $345,000, what is the monthly payment if you put 10% down for a 30 year loan with a fixed r
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It would be <span>b.<span>$1,937.12.

Thank you! I am sorry if this was a bit late.
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