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3 years ago

Please help with the attachment below! I forgot how to do these xD

Mathematics

2 answers:

Triss [41]3 years ago

8 0

Use Mathpapa or symbolab, they are both very useful resources, and have saved me many times

Vadim26 [7]3 years ago

4 0

So what you to is apply the exponent rule: x^a/x^b = x^(a-b)

which gives you 4^-2/4^-4 = 4^(-2-(-4))

simplify that to 4^2
then simplify that and that's your answer :P

You might be interested in

Seventy-two percent of the light aircraft that disappear while in flight in a certain country are subsequently discovered. Of th

Anton [14]

Answer:

a) 0.105 = 10.5% probability that it will not be discovered if it has an emergency locator.

b) 0.522 = 52.2% probability that it will be discovered if it does not have an emergency locator.

c) 0.064 = 6.4% probability that 7 of them are discovered.

Step-by-step explanation:

For itens a and b, we use conditional probability.

For item c, we use the binomial distribution along with the conditional probability.

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.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

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

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

And p is the probability of X happening.

a) If it has an emergency locator, what is the probability that it will not be discovered?

Event A: Has an emergency locator

Event B: Not located.

Probability of having an emergency locator:

66% of 72%(Are discovered).

20% of 100 - 72 = 28%(not discovered). So

$P(A) = 0.66*0.72 + 0.2*0.28 = 0.5312$

Probability of having an emergency locator and not being discovered:

20% of 28%. So

$P(A cap B) = 0.2*0.28 = 0.056$

Probability:

$P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.056}{0.5312} = 0.105$

0.105 = 10.5% probability that it will not be discovered if it has an emergency locator.

b) If it does not have an emergency locator, what is the probability that it will be discovered?

Probability of not having an emergency locator:

0.5312 of having. So

$P(A) = 1 - 0.5312 = 0.4688$

Probability of not having an emergency locator and being discovered:

34% of 72%. So

$P(A \cap B) = 0.34*0.72 = 0.2448$

Probability:

$P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.2448}{0.4688} = 0.522$

0.522 = 52.2% probability that it will be discovered if it does not have an emergency locator.

c) If we consider 10 light aircraft that disappeared in flight with an emergency recorder, what is the probability that 7 of them are discovered?

p is the probability of being discovered with the emergency recorder:

0.5312 probability of having the emergency recorder.

Probability of having the emergency recorder and being located:

66% of 72%. So

$P(A \cap B) = 0.66*0.72 = 0.4752$

Probability of being discovered, given that it has the emergency recorder:

$p = P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.4752}{0.5312} = 0.8946$

This question asks for P(X = 7) when $n = 10$ . So

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 7) = C_{10,7}.(0.8946)^{7}.(0.1054)^{3} = 0.064$

0.064 = 6.4% probability that 7 of them are discovered.

8 0

3 years ago

Which undefined terms are needed to define parallel lines

Alexandra [31]

Parallel lines are coplanar lines that do not intersect

6 0

3 years ago

The USDA reported that in 1990 each person in the United States consumed an average of 133 pounds of natural sweeteners. They al

blsea [12.9K]

Answer:

The problem implies that we want to write the (average) amount of natural sweeteners consumed per person as a function of time. Let y represent the (average) amount of natural sweeteners consumed per person (in pounds), and let x represent the time measured in years since 1990. That is, x = 0 represents 1990. If y is a linear function of x, then we can use the slope-intercept form y = mx + b (where m is the slope and b is the y-intercept) to write the function.

The slope can be interpreted as the rate of change of y with respect to x, which in this case means the change in consumption of natural sweeteners per year. The statement that consumption has decreased by 0.6 pounds per year tells us that the slope is m = -0.6 Also, the y-intercept is the same as the y-value of the function when x = 0. (In our case, that means time 0, that is, 1990.) Therefore the y-intercept is b = 133. Hope that helps! Let me know if you have any further questions.

Step-by-step explanation:

6 0

4 years ago

Read 2 more answers

A rectangular garden must have a perimeter of 155 feet and an area of at least 1400 square feet. Describe the possible lengths o

snow_lady [41]

Answer:

Step-by-step explanation:

Perimeter of a garden = 2(L+W)

Area of the gerden = LW

L is the length

W is the width

Given

Perimeter = 155ft

Area = 1400ft²

Substitute

1400 = LW

155 = 2L+2W

from 1;

W = 1400/L

Substitute into 2;

155 = 2L + 2(1400/L)

155 = 2L + 2800/L

155L = 2L² + 2800

2L²-155L + 2800 = 0

Factorize

L = 155±√155²-4(2)(2800)/4

L = 155±√24025-22400/4

L = 155±√1625/4

L = L = 155±40.31/4

L = 194.31/4

L = 48.82 feet and;

L = 155-40.31/4

L = 28.67ft

Hence the approximate length of the garden is at least 28.67 feet and at most 48.82 feet.

6 0

3 years ago

2p-b=c-ap solve for tems of p so p=bla bla bla

vitfil [10]

2p-b=c-ap

2p+ap=c+b

p(2+a)=c+b

So, p=(c+b)/(2+a)

3 0

3 years ago

Read 2 more answers