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IgorLugansk [536]
2 years ago
8

Evaluate S5 for 400 + 200 + 100 + … and select the correct answer below.

Mathematics
2 answers:
Strike441 [17]2 years ago
7 0

Answer:


Step-by-step explanation:

This question asks for the sum of the first 5 terms of the series.

Looking at the first 3 terms, we can see that each successive term is half of the one before it.

<em>So next term after 100 would be 50. Next term after 50 would be 25.</em>


Thus, we can write:

400 + 200 + 100 + 50 + 25 + ...

We already have first 5 terms, the sum is:

400 + 200 + 100 + 50 + 25 = 775

Answer choice B is right.

Nadusha1986 [10]2 years ago
5 0
The correct answer is B) 775 

Why 775? Because Assume the series continues.

400+200+100+50+25=775

I hope this helps. 

Have a great day. :)
You might be interested in
Pete and Marsha are going to buy a swimming pool. Mike wants a rectangular one that is 18 feet wide, 20 feet long, and 6 feet de
maks197457 [2]

Answer:

The pool that they buy is the circular pool which Marsha wants

The cost of the circular pool is $471.25

Step-by-step explanation:

The parameters of the swimming pools which each of Pete and Marsha wants to buy is given as follows;

The dimensions of the pool Pete wants = 18 feet wide, 20 feet long and 6 feet deep

The dimensions of the circle shaped pool Marsha wants = 20 feet across and 6 feet deep

The price of water, P = 25 cents per cubic foot

The pool they decide to buy = The pool that costs less to fill

The volume of water to fill the pool Pete wants, V₁ = 18 ft. × 20 ft. × 6 ft. = 2,160 ft.³

The cost of filling the pool Pete wants, C₁ = V₁ × P

∴ C₁ = 2,160 ft.³ × 25cents/ft.³ = 54,000 cents = 540 Dollars

The volume of water to fill the pool Marsha wants, V₂ = π·(20 ft.)²/4 × 6 ft. ≈ 1,884.96 ft.³

The cost of filling the pool Marsha wants, C₁ = V₁ × P

∴ C₁ ≈ 1,884.96 ft.³ × 25 cents/ft.³ ≈ 47,124 cents = 471.24 Dollars

The pool that they buy is the circular pool that Marsha wants and it costs $471.24 to fill

5 0
2 years ago
Which expressions are equivalent to the one below? Check all that apply.
In-s [12.5K]
The answer is E:5
a^n/b^m=a/b^n/m
So x/x=1 and 25/5=5
Then 5^1=5
3 0
3 years ago
Read 2 more answers
Solve 3k^2=8k+8,using completing the square method ​
GenaCL600 [577]

Answer:

3k2=8k+8 

Two solutions were found :

 k =(8-√160)/6=(4-2√ 10 )/3= -0.775

 k =(8+√160)/6=(4+2√ 10 )/3= 3.442

Reformatting the input :

Changes made to your input should not affect the solution:

 (1): "k2"   was replaced by   "k^2". 

Rearrange:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation : 

                     3*k^2-(8*k+8)=0 

Step by step solution :

Step  1  :

Equation at the end of step  1  :

3k2 - (8k + 8) = 0

Step  2  :

Trying to factor by splitting the middle term

 2.1     Factoring  3k2-8k-8 

The first term is,  3k2  its coefficient is  3 .

The middle term is,  -8k  its coefficient is  -8 .

The last term, "the constant", is  -8 

Step-1 : Multiply the coefficient of the first term by the constant   3 • -8 = -24 

Step-2 : Find two factors of  -24  whose sum equals the coefficient of the middle term, which is   -8 .

     -24   +   1   =   -23     -12   +   2   =   -10     -8   +   3   =   -5     -6   +   4   =   -2     -4   +   6   =   2     -3   +   8   =   5     -2   +   12   =   10     -1   +   24   =   23

Observation : No two such factors can be found !! 

Conclusion : Trinomial can not be factored

Equation at the end of step  2  :

3k2 - 8k - 8 = 0

Step  3  :

Parabola, Finding the Vertex :

 3.1      Find the Vertex of   y = 3k2-8k-8

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, 3 , 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,Ak2+Bk+C,the  k -coordinate of the vertex is given by  -B/(2A) . In our case the  k  coordinate is   1.3333  

 Plugging into the parabola formula   1.3333  for  k  we can calculate the  y -coordinate : 

  y = 3.0 * 1.33 * 1.33 - 8.0 * 1.33 - 8.0 

or   y = -13.333

Parabola, Graphing Vertex and X-Intercepts :

Root plot for :  y = 3k2-8k-8

Axis of Symmetry (dashed)  {k}={ 1.33} 

Vertex at  {k,y} = { 1.33,-13.33}  

 k -Intercepts (Roots) :

Root 1 at  {k,y} = {-0.77, 0.00} 

Root 2 at  {k,y} = { 3.44, 0.00} 

Solve Quadratic Equation by Completing The Square

 3.2     Solving   3k2-8k-8 = 0 by Completing The Square .

 Divide both sides of the equation by  3  to have 1 as the coefficient of the first term :

   k2-(8/3)k-(8/3) = 0

Add  8/3  to both side of the equation : 

   k2-(8/3)k = 8/3

Now the clever bit: Take the coefficient of  k , which is  8/3 , divide by two, giving  4/3 , and finally square it giving  16/9 

Add  16/9  to both sides of the equation :

  On the right hand side we have :

   8/3  +  16/9   The common denominator of the two fractions is  9   Adding  (24/9)+(16/9)  gives  40/9 

  So adding to both sides we finally get :

   k2-(8/3)k+(16/9) = 40/9

Adding  16/9  has completed the left hand side into a perfect square :

   k2-(8/3)k+(16/9)  =

   (k-(4/3)) • (k-(4/3))  =

  (k-(4/3))2 

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

   k2-(8/3)k+(16/9) = 40/9 and

   k2-(8/3)k+(16/9) = (k-(4/3))2 

then, according to the law of transitivity,

   (k-(4/3))2 = 40/9

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

   (k-(4/3))2   is

   (k-(4/3))2/2 =

  (k-(4/3))1 =

   k-(4/3)

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

   k-(4/3) = √ 40/9 

Add  4/3  to both sides to obtain:

   k = 4/3 + √ 40/9 

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

   k2 - (8/3)k - (8/3) = 0

   has two solutions:

  k = 4/3 + √ 40/9 

   or

  k = 4/3 - √ 40/9 

Note that  √ 40/9 can be written as

  √ 40  / √ 9   which is √ 40  / 3 

Solve Quadratic Equation using the Quadratic Formula

 3.3     Solving    3k2-8k-8 = 0 by the Quadratic Formula .

 According to the Quadratic Formula,  k  , the solution for   Ak2+Bk+C  = 0  , where  A, B  and  C  are numbers, often called coefficients, is given by :

                                     

            - B  ±  √ B2-4AC

  k =   ————————

                      2A 

  In our case,  A   =     3

                      B   =    -8

                      C   =   -8 

Accordingly,  B2  -  4AC   =

                     64 - (-96) =

                     160

Applying the quadratic formula :

               8 ± √ 160 

   k  =    —————

                    6

Can  √ 160 be simplified ?

Yes!   The prime factorization of  160   is

   2•2•2•2•2•5  

To be able to remove something from under the radical, there have to be  2  instances of it (because we are taking a squarei.e. second root).

√ 160   =  √ 2•2•2•2•2•5   =2•2•√ 10   =

                ±  4 • √ 10 

  √ 10   , rounded to 4 decimal digits, is   3.1623

 So now we are looking at:

           k  =  ( 8 ± 4 •  3.162 ) / 6

Two real solutions:

 k =(8+√160)/6=(4+2√ 10 )/3= 3.442 

or:

 k =(8-√160)/6=(4-2√ 10 )/3= -0.775 

Two solutions were found :

 k =(8-√160)/6=(4-2√ 10 )/3= -0.775

 k =(8+√160)/6=(4+2√ 10 )/3= 3.442

5 0
2 years ago
Read 2 more answers
Two angle measures in a triangle are 47 degrees and 43 degrees. what type of triangle is it?
Maslowich
Take 180 subtract 47 and 43.  You get 90.  So it would be C. 
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A Walmart truck driver estimates that it will take him 12 hours to drive 1152 km. After 5 hours, he has driven 520 km.
san4es73 [151]

(a) He would drive 96 km in an hour because 1152 divided by 12 is 96

(b) He is technically on schedule because he is driving 104 km per hour, instead of 96, so if he keeps driving at the same rate, he should get there in under 12 hours

6 0
2 years ago
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