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2 years ago

15

A group of 11 students have a mean average spelling test score of 7. Another student had a score of 8. What is the mean score of

all twelve children?

1 answer:

Elena L [17]2 years ago

7 0

Answer:

7.083

Step-by-step explanation:

You might be interested in

If the endpoints of the diameter of a circle are (−8, −6) and (−4, −14), what is the standard form equation of the circle?

kondaur [170]

Equation of the circle is $(x+6)^{2}+(y+10)^{2}=20$ .

Solution:

The endpoints of the diameter of a circle are (–8, –6) and (–4, –14).

Center of the circle = Mid point of the diameter

Mid point formula:

$$P(x, y)=\left(\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2}\right)$

Here, $x_1=-8, y_1=-6, x_2=-4, y_2=-14$

$$P(x, y) =\left(\frac{-8-4}{2}, \frac{-6-14}{2}\right)$

$$P(x, y) =\left(\frac{-12}{2}, \frac{-20}{2}\right)$

$$P(x, y) =(-6, -10)$

Center of the circle = (–6, –10)

Radius is the distance between center and any endpoint of the diameter.

To calculate the radius using distance formula.

$r=\sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}}$

Here, $x_1=-6, y_1=-10, x_2=-8, y_2=-6$

$r=\sqrt{\left(-8-(-6)\right)^{2}+\left(-6-(-10)}\right)^{2}}$

$r=\sqrt{(-8+6)^{2}+(-6+10)^{2}}$

$r=\sqrt{(-2)^{2}+(4)^{2}}$

$r=\sqrt{20}$ units

The standard form of the equation of a circle is

$(x-a)^{2}+(y-b)^{2}=r^{2}$ , where (a, b) are center and r is the radius.

Here, center = (–6, –10) and $r=\sqrt{20}$

$(x-(-6))^{2}+(y-(-10))^{2}={(\sqrt{20})} ^{2}$

$(x+6)^{2}+(y+10)^{2}=20$

Equation of the circle is $(x+6)^{2}+(y+10)^{2}=20$ .

4 0

3 years ago

Out of 21 students in Mrs.Clarks class, 3/7 of the class are boys and 4/7 are girls. How many students in the class are girls an

lidiya [134]

Answer:

9 boys and 12 girls

Step-by-step explanation:

if you multiply the denominators by 3, you get "out of" 21. All you need to do after that is multiply the top by 3 as well and it tells you there are 9 boys and 12 girls.

8 0

3 years ago

Simplify the following expression completely using distribution and combining like terms

LiRa [457]

$\huge \boxed{\mathbb{QUESTION} \downarrow}$

Simplify ⇨ 19m + 14 - 3 (3m + 7)

$\large \boxed{\mathfrak{Answer \: with \: Explanation} \downarrow}$

$\sf \: 19 m - 14 - 3 ( 3 m + 7 )$

Use the distributive property to multiply -3 by 3m+7.

$\sf \: 19m-14-9m-21$

Combine 19m and -9m to get 10m.

$\sf \: 10m-14-21$

Subtract 21 from -14 to get -35.

$\boxed{\boxed{\bf \: 10m-35 }}$

5 0

2 years ago

What is the perimeter of this tile?

Slav-nsk [51]

Answer:

6x2=12

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

Express with radical signs instead of fractional exponents. Rationalize the denominator.

CaHeK987 [17]

$x^{\frac{1}{2}} = \sqrt[2]{x}$ and $3^{-\frac{1}{2}} = \frac{1}{3^{\frac{1}{2}} } = \frac{1}{\sqrt[2]{3}}$ so

$3^{-\frac{1}{2}} x^{\frac{1}{2}} = \frac{1}{\sqrt{3}} \cdot \sqrt{x} = \frac{\sqrt{x}}{\sqrt{3}}$

and you rationalize denominator by multiplying numerator and denominatr by $\sqrt{3}$ so that gives--

$\frac{\sqrt{x}}{\sqrt{3}} \cdot \frac{\sqrt{3}}{\sqrt{3}} = \frac{\sqrt{3x}}{3}$

Your answer is $\frac{\sqrt{3x}}{3}$

5 0

3 years ago