What is the unit rate of 420 miles in 7 hours

26. A book costs sh. (x - 300) and a pen costs sh (x + 100). If Ndagire pad sh. 3300 for 3 books and 2 pens, how much did she pa

saul85 [17]

Answer:

500 and 900

Step-by-step explanation:

3(x - 300) + 2(x + 100) = 3300 ← distribute parenthesis

3x - 900 + 2x + 200 = 3300

5x - 700 = 3300 ( add 700 to both sides )

5x = 4000 ( divide both sides by 5 )

x = 800

Then

cost of book = x - 300 = 800 - 300 = 500

cost of pen = x + 100 = 800 + 100 = 900

7 0

2 years ago

Easy 100 points, plz answer ASP! Please include an explanation!!

valina [46]

Answer:

The third option

Step-by-step explanation:

the most reasonable

6 0

3 years ago

Read 2 more answers

Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviat

drek231 [11]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

Step-by-step explanation:

For this case we have the following probability distribution given:

X 0 1 2 3 4 5

P(X) 0.031 0.156 0.313 0.313 0.156 0.031

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

We can verify that:

$\sum_{i=1}^n P(X_i) = 1$

And $P(X_i) \geq 0, \forall x_i$

So then we have a probability distribution

We can calculate the expected value with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

6 0

4 years ago

A deck of 52 cards is dealt out to 4 players. what is the probability that one of the players receive all 13 hearts

photoshop1234 [79]

13/204 is the answer

3 0

3 years ago

The length of a rectangle is 8 inches longer than half of its width.The area of the rectangle is 18 square inches.How many inche

SOVA2 [1]

Answer:

The correct answer is 2 inches.

Step-by-step explanation:

Let l inches and w inches be the length and width of a rectangle respectively.

According to the given problem, l - 8 = $\frac{w}{2}$ .

Area of the rectangle is given to be, according to the question, 18 square inches.

Thus l × w = 18

⇒ l × (2l - 16) = 18

⇒ 2 $l^{2}$ - 16l - 18 = 0

⇒ $l^{2}$ - 8l - 9 = 0

⇒ ( l - 9) ( l + 1) = 0

The possible values of l are 9 and -1. As the length cannot be equal to -1, thus the value of the length is 9 inches.

Width of the rectangle is 2 inches.

5 0

4 years ago