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2 years ago

11

Xiomara bought 3 books that each cost the same amount and a magazine for a total of $27. If the magazine cost $3, then how much

was each book? Write an equation and solve.

2 answers:

pychu [463]2 years ago

7 0

$7 is 1/6 of 3/7 of Bella's money, so she had $98 to start with. 4/7 of 98 is $56, as you figured.

The dictionary and the books cost 56

d+3b = 56

3/8 d = 1/2 * 3b

so, 3d = 12b

4b + 3b = 56

b = 8

check:

3 books cost 24

dictionary cost 32

3/8(32) = 1/2(24)

12=12

skelet666 [1.2K]2 years ago

4 0

Answer:$8

Step-by-step explanation:

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One satellite is scheduled to be launched from Cape Canaveral in Florida, and another launching is scheduled for Vandenberg Air

Lisa [10]

Answer:

$P(A) = 0.45$

$P(B) = 0.32$

Step-by-step explanation:

Given

$P(A) > P(B)$

$P(A\ u\ B) = 0.626$

$P(A\ n\ B) = 0.144$

Required

Find P(A) and P(B)

We have that:

$P(A\ u\ B) = P(A) + P(B) - P(A\ n\ B)$ --- (1)

and

$P(A\ n\ B) = P(A) * P(B)$ --- (2)

The equations become:

$P(A\ u\ B) = P(A) + P(B) - P(A\ n\ B)$ --- (1)

$0.626 = P(A) + P(B) - 0.144$

Collect like terms

$P(A) + P(B) = 0.626 + 0.144$

$P(A) + P(B) = 0.770$

Make P(A) the subject

$P(A) = 0.770 - P(B)$

$P(A\ n\ B) = P(A) * P(B)$ --- (2)

$0.144 = P(A) * P(B)$

$P(A) * P(B) = 0.144$

Substitute: $P(A) = 0.770 - P(B)$

$[0.770 - P(B)] * P(B) = 0.144$

Open bracket

$0.770P(B) - P(B)^2 = 0.144$

Represent P(B) with x

$0.770x - x^2 = 0.144$

Rewrite as:

$x^2 - 0.770x + 0.144 = 0$

Expand

$x^2 - 0.45x - 0.32x + 0.144 = 0$

Factorize:

$x[x - 0.45] - 0.32[x - 0.45]= 0$

Factor out x - 0.45

$[x - 0.32][x - 0.45]= 0$

Split

$x - 0.32= 0 \ or\ x - 0.45= 0$

Solve for x

$x = 0.32\ or\ x = 0.45$

Recall that:

$P(B) = x$

So, we have:

$P(B) = 0.32 \ or \ P(B) = 0.45$

Recall that:

$P(A) = 0.770 - P(B)$

So, we have:

$P(A) = 0.770 - 0.32 \ or\ P(A) =0.770 - 0.45$

$P(A) = 0.45 \ or\ P(A) =0.32$

Since:

$P(A) > P(B)$

Then:

$P(A) = 0.45$

$P(B) = 0.32$

6 0

2 years ago

The distribution of speeds on a particular highway has a mean of 60 mph with a standard deviation of 10 mph. The distribution of

PSYCHO15rus [73]

Answer:

a) At least what percentage of cars is traveling between 40 and 80 mph?

75%

b) At least what percentage of cars is traveling between 20 and 100 mph?

93.75%

c) If a sample of 40 cars is selected at random, estimate the number of cars that are traveling between 40 and 80 mph.

30 cars.

Step-by-step explanation:

We apply Chebyshev's Theorem

This states that:

1) At least 3/4 (75%) of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.

2) At least 8/9 (88.89%) of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ.

3) At least 15/16 (93.75%) of data falls within 4 standard deviations from the mean - between μ - 4σ and μ + 4σ.

From the question, we have:

Mean of 60 mph

Standard deviation of 10 mph.

a) At least what percentage of cars is traveling between 40 and 80 mph?

Applying:

Applying the first rule: At least 3/4 (75%) of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ.

μ – 2σ

60 - 2(10)

60 - 20

= 40 mph

μ + 2σ.

60 + 2(10)

60 + 20

= 80 mph

Hence, at least 75% of cars is traveling between 40 and 80 mph.

b) At least what percentage of cars is traveling between 20 and 100 mph?

At least 15/6 (93.75%) of data falls within 4 standard deviations from the mean - between μ – 4σ and μ + 4σ.

μ – 4σ

60 - 4(10)

60 - 40

= 20 mph

μ + 4σ.

60 + 4(10)

60 + 40

= 100 mph

Hence, at least 93.75% of cars is traveling between 40 and 80 mph.

c) If a sample of 40 cars is selected at random, estimate the number of cars that are traveling between 40 and 80 mph.

Since we know from question a) that

at least 75% of cars is traveling between 40 and 80 mph.

Given a sample of 40 cars:

75% of 40 cars

= 75/100 × 40

= 30 cars.

The number of cars that are traveling between 40 and 80 mph is 30 cars.

5 0

2 years ago

lana66690 [7]

Answer:

C is correct.

Step-by-step explanation:

This is true because B and C go up 5 on the y-axis to get to B' and C', but A goes up 6, making it not a translation.

8 0

3 years ago

Read 2 more answers

First, if the altitude drawn to the hypotenuse of a right triangle divides the hypotenuse into two segments with lengths of 9 in

Serhud [2]

A right triangle base in your question, its hypotenuse is divided in to two line segment by a line of altitude and those segment are measured as 9 inches and 17 inches, so base on my calculation the exact length of the altitude is 3*sqrt(17)

8 0

2 years ago

Will give brainliest for right answer!!

Katen [24]

Answer:

3012 books

Step-by-step explanation:

Let y = number of books produced and sold

Total cost = Fixed cost + Variable cost = 32379 + 10.75*y

Total sales = 21.50*y

Set these equal to each other and solve for y

21.50*y = 32379 + 10.75*y

10.75*y = 32379

B = 3012

The publisher must produce and sell 3012 books.

3 0

2 years ago