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3 years ago

9

Giles is searching for a sock and discovers that he has 10 socks for every 5 pairs of shoes. If he has 20 socks, how many pairs

of shoes does he have?

1 answer:

Firlakuza [10]3 years ago

7 0

Answer:

he has 10 pairs of shoes

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Gabriela has taken 33 quizzes and her average score so far is 8080. if she gets 100100, a perfect score, on the remaining 22 qui

allochka39001 [22]

Her average will be 100078

7 0

3 years ago

Hello my name is Sam and I have some homework that is due today, how is g 125 degrees? You will get a guaranteed brainliest if y

VLD [36.1K]

Hi sam, do you want to know the answer? Try using a protractor, you will see the degree is 125, its like a obtuse angle

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2 years ago

Find the product of all real values of r for which 1/2x=r-x/7

Dahasolnce [82]

Answer:

$r = \±\sqrt{14$

$Product = -14$

Step-by-step explanation:

Given

$\frac{1}{2x} = \frac{r - x}{7}$

Required

Find all product of real values that satisfy the equation

$\frac{1}{2x} = \frac{r - x}{7}$

Cross multiply:

$2x(r - x) = 7 * 1$

$2xr - 2x^2 = 7$

Subtract 7 from both sides

$2xr - 2x^2 -7= 7 -7$

$2xr - 2x^2 -7= 0$

Reorder

$- 2x^2+ 2xr -7= 0$

Multiply through by -1

$2x^2 - 2xr +7= 0$

The above represents a quadratic equation and as such could take either of the following conditions.

(1) No real roots:

This possibility does not apply in this case as such, would not be considered.

(2) One real root

This is true if

$b^2 - 4ac = 0$

For a quadratic equation

$ax^2 + bx + c = 0$

By comparison with $2x^2 - 2xr +7= 0$

$a = 2$

$b = -2r$

$c =7$

Substitute these values in $b^2 - 4ac = 0$

$(-2r)^2 - 4 * 2 * 7 = 0$

$4r^2 - 56 = 0$

Add 56 to both sides

$4r^2 - 56 + 56= 0 + 56$

$4r^2 = 56$

Divide through by 4

$r^2 = 14$

Take square roots

$\sqrt{r^2} = \±\sqrt{14$

$r = \±\sqrt{14$

Hence, the possible values of r are:

$\sqrt{14$ or $-\sqrt{14$

and the product is:

$Product = \sqrt{14} * -\sqrt{14}$

$Product = -14$

8 0

3 years ago

Suppose we roll a fair six-sided die 20 times and draw ten cards from a standard 52-card deck. Let X be the number of "6"s rolle

Lera25 [3.4K]

Answer:

a) Expected value = 6.406

Variance = 4.905

Standard deviation = 2.45

b) The probability is 0.08547

Step-by-step explanation:

a) Let's suppose that:

X₁ = number of 6´s

X₂ = number of Jack, Queen, King or Aces

The mean of X₁ is:

MeanX₁ = n * p = 20 * (1/6) = 3.33

The variance of X₁ is:

$Var-X_{1} =np(1-p)=3.33(1-(1/6))=2.775$

The mean of X₂ is:

MeanX₂ = 10 * (16/52) = 3.076

The variance of X₂ is:

$Var-X_{2} =3.076(1-(16/52))=2.13$

The expect value of X is:

Xexp = MeanX₁ + MeanX₂ = 3.33 + 3.076 = 6.406

The variance of X is:

VarX = VarX₁ + VarX₂ = 2.775 + 2.13 = 4.905

The standard deviation is:

Xdevi = 4.905/2 = 2.45

b) The probability of drawing at least five six out of 20 rolls is equal to:

∑(1/6)ˣ(5/6)²⁰⁻ˣ = 0.231 with x = 5

The probability of at least 4 Jack, Queen, Kings or Aces is:

∑(16/52)ˣ(1-(16/52))¹⁰⁻ˣ = 0.37 with x = 4

The probability of given event is equal to:

P = 0.231 * 0.37 = 0.08547

5 0

3 years ago

Using the Quadratic Formula, which of the following is the solution to the quadratic equation x2 + 2x - 3 = 0?

saw5 [17]

Answer: x=1 or x=-3

Step-by-step explanation:

Quadratic formula is $-b+-\sqrt{b^{2}-4ac } /2$

a=1 b=2 c=-3

Substitute

$(-2+-\sqrt{2^{2}-4(1)(-3) }) /2\\(-2+-\sqrt{4+12}) /12\\(-2+-\sqrt{16}) /2\\(-2+-4) /2\\x=\frac{-2+4}{2} \\x=\frac{-2-4}{2} \\\\\\Simplify\\x=\frac{2}{2} \\\\x=\frac{-6}{2} \\\\Simplify\\x=1\\x=-3$

6 0

3 years ago