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SVETLANKA909090 [29]

2 years ago

12

I need help with this question pleas urgent!

1 answer:

BaLLatris [955]2 years ago

3 0

Answer:

75.5

Step-by-step explanation:

To calculate the mean we use

mean = $\frac{score}{count}$

To calculate the mean for class B we require their score

Using the mean for class A

$\frac{score}{25}$ = 67.8 ( multiply both sides by 25 )

score = 67.8 × 25 = 1695

Similarly using the mean for all 55 students

$\frac{totalscore}{55}$ = 72 ( multiply both sides by 55 )

total score = 72 × 55 = 3960

Hence score for class B = 3960 - 1695 = 2265

mean for class B = $\frac{2265}{30}$ = 75.5

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Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth.

likoan [24]

Answer:

Thus, the two root of the given quadratic equation $x^2+4=6x$ is 5.24 and 0.76 .

Step-by-step explanation:

Consider, the given Quadratic equation, $x^2+4=6x$

This can be written as , $x^2-6x+4=0$

We have to solve using quadratic formula,

For a given quadratic equation $ax^2+bx+c=0$ we can find roots using,

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$ ...........(1)

Where, $\sqrt{b^2-4ac}$ is the discriminant.

Here, a = 1 , b = -6 , c = 4

Substitute in (1) , we get,

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

$\Rightarrow x=\frac{-(-6)\pm\sqrt{(-6)^2-4\cdot 1 \cdot (4)}}{2 \cdot 1}$

$\Rightarrow x=\frac{6\pm\sqrt{20}}{2}$

$\Rightarrow x=\frac{6\pm 2\sqrt{5}}{2}$

$\Rightarrow x={3\pm \sqrt{5}}$

$\Rightarrow x_1={3+\sqrt{5}}$ and $\Rightarrow x_2={3-\sqrt{5}}$

We know $\sqrt{5}=2.23607$ (approx)

Substitute, we get,

$\Rightarrow x_1={3+2.23607}$ (approx) and $\Rightarrow x_2={3-2.23607}$ (approx)

$\Rightarrow x_1={5.23607}$ (approx) and $\Rightarrow x_2=0.76393}$ (approx)

Thus, the two root of the given quadratic equation $x^2+4=6x$ is 5.24 and 0.76 .

7 0

2 years ago

Read 2 more answers

Find the greatest common factor of the<br> following monomials:<br> 15r25<br> 48353

Cerrena [4.2K]

Answer:

475r35

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

Please answer fast its timed

Alborosie

Answer:

f(5) = 22

f(9) = 34

Step-by-step explanation:

Plug in 5 and 9 separately for the equation of the x values. Multiply them each and add 7 to get these values 22 and 34.

4 0

3 years ago

John is driving around town. When he reaches the gas station, he notes that he has traveled 20 miles. He reaches home 2 hours la

Troyanec [42]

Answer:

$d=5t+20$

Step-by-step explanation:

The equation that will model this situation will be of the form

$d=mt+b$

where $t$ is the time in hours john has traveled since the gas station, and $d$ is the distance.

Now we know that John has already traveled 20 miles when he is at the gas station, this means at $t=0$ , $d=20$ ; or

$20=m(0)+b$

$\boxed{b=20}$

Thus we have

$d=mt+20$ .

Now we need to figure out $m.$

When John reaches home 2 hours later he notes that he has traveled 30 miles, which means he has traveled 30 - 20 = 10 miles; thus we have

$m= \frac{\Delta d}{\Delta t} =\frac{10 miles}{2hours} =5$

$\boxed{m=5}$

Now we have the full equation:

$\boxed{d=5t+20}$

8 0

2 years ago

Four added to twice a number yield 26/5. Find the number.<br>

avanturin [10]

Answer:

3/5 is the answer

sry if it's wrong

8 0

2 years ago

Read 2 more answers