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3 years ago

8

In 1924, the temperature in Fairfield, Montana, dropped from 63 degrees to -21 degrees in 12 hours. What was the average hourly

change in temperature.

1 answer:

Pavlova-9 [17]3 years ago

4 0

The average change hourly is 7 degrees per hour

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Use the perfect square method <br> (3x + 3)^2 = 36

kkurt [141]

Factor out the common term; 3

(3(x + 1))^2 = 36

Use the Multiplication Distributive Property; (xy)^a = x^ay^a

3^2(x + 1)^2 = 36

Simplify 3^2 to 9

9(x + 1)^2 = 36

Divide both sides by 9

(x + 1)^2 = 36/9

Simplify 36/9 to 4

(x + 1)^2 = 4

Take the square root of both sides

x + 1 = √4

Since 2 * 2 = 4, the square root of 2 is 2

x + 1 = 2

Break down the problem into these 2 equations

x + 1 = 2

x + 1 = -2

Solve the first equation; x + 1 = 2

x = 1

Solve the second equation; x + 1 = -2

x = -3

Collect all solutions;

<u>x = 1, -3</u>

8 0

3 years ago

What is the area of a trapezium

krok68 [10]

1
— l( a+b)
2

It is the area of trapezium

4 0

3 years ago

Hii I just wasn't sure about how to answer this so could someone help?

balandron [24]

Answer:

1/2

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

A bag contains 4 blue marbles and 2 yellow marbles. Two marbles are randomly chosen (the first marble is NOT replaced before dra

VMariaS [17]

Answer:

0.4 = 40% probability that both marbles are blue.

0.0667 = 6.67% probability that both marbles are yellow.

53.33% probability of one blue and then one yellow

If you are told that both selected marbles are the same color, 0.8571 = 85.71% probability that both are blue

Step-by-step explanation:

To solve this question, we need to understand conditional probability(for the final question) and the hypergeometric distribution(for the first three, because the balls are chosen without being replaced).

Hypergeometric distribution:

The probability of x sucesses is given by the following formula:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

In which:

x is the number of sucesses.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

Conditional Probability

We use the conditional probability formula to solve this question. It is

$P(B|A) = \frac{P(A \cap B)}{P(A)}$

In which

P(B|A) is the probability of event B happening, given that A happened.

$P(A \cap B)$ is the probability of both A and B happening.

P(A) is the probability of A happening.

What is the probability that both marbles are blue?

4 + 2 = 6 total marbles, which means that $N = 6$

4 blue, which means that $k = 4$

Sample of 2, which means that $n = 2$

This is P(X = 2). So

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,6,2,4) = \frac{C_{4,2}*C_{2,0}}{C_{6,2}} = 0.4$

0.4 = 40% probability that both marbles are blue

What is the probability that both marbles are yellow?

4 + 2 = 6 total marbles, which means that $N = 6$

2 yellow, which means that $k = 2$

Sample of 2, which means that $n = 2$

This is P(X = 2). So

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,6,2,2) = \frac{C_{2,2}*C_{4,0}}{C_{6,2}} = 0.0667$

0.0667 = 6.67% probability that both marbles are yellow.

What is the probability of one blue and then one yellow?

Total is 100%.

Can be:

Both blue(40%)

Both yellow(6.67%)

One blue and one yellow(x%). So

40 + 6.67 + x = 100

x = 100 - 46.67

x = 53.33

53.33% probability of one blue and then one yellow.

If you are told that both selected marbles are the same color, what is the probability that both are blue?

Conditional probability.

Event A: Both same color

Event B: Both blue

Probability of both being same color:

Both blue(40%)

Both yellow(6.67%)

This means that $P(A) = 0.4 + 0.0667 = 0.4667$

Probability of both being the same color and blue:

40% probability that both are blue, which means that $P(A \cap B) = 0.4$

Desired probability:

$P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.4}{0.4667} = 0.8571$

If you are told that both selected marbles are the same color, 0.8571 = 85.71% probability that both are blue

8 0

2 years ago

AB = 2x-5 BC = 6x AC = 27

OlgaM077 [116]

Answer:

correct answer is x = 2.75

Step-by-step explanation:

Given;

AB = 2x-5

BC = 6x

AC = 27

Hence,

=> AC = AB + BC

=> 27 = 2x-5 + 6x

=> 27 = 8x-5

=> 27-5 = 8x

=> 22 = 8x

=> 22/8 = x

=> 11/4 = x

or

2.75 = x

3 0

2 years ago