Express as a sum: a-5 m-n Express as a difference: 7+3 a+5 a+b

Benny is trying to learn how to ride a bike, but is terrified of falling. He did some research, and discovered that if he rides

Anestetic [448]

Answer:

a) 7.14% probability that Benny was learning to ride a bike using the training wheels

b) 28% probability that Benny was learning to ride a bike using the training wheels

Step-by-step explanation:

Bayes Theorem:

Two events, A and B.

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

In which P(B|A) is the probability of B happening when A has happened and P(A|B) is the probability of A happening when B has happened.

Benny came home crying with a bruise on his knee, after falling. His mom is trying to guess how Benny was trying to learn to ride a bike.

a) Assuming that the probability that Benny was using each of these 3 methods is equal, what is the probability that Benny was learning to ride a bike using the training wheels?

So

Event A: Benny fell

Event B: Benny was using training wheels.

The probability that Benny was using each of these 3 methods is equal

This means that $P(B) = \frac{1}{3}$

He did some research, and discovered that if he rides a bike with training wheels, the probability of falling is 0.1;

This means that $P(A|B) = 0.1$

Probability of falling:

1/3 of the time, he uses training wheels. With training wheels, the probability of falling is 0.1.

1/3 of the time, he uses the bike without training wheels. Without training wheels, the probability of falling is 0.5

1/3 of the time, he uses the unicycle, for which he has an 0.8 probability of falling. Then

$P(A) = \frac{0.1 + 0.5 + 0.8}{3} = 0.4667$

So

$P(B|A) = \frac{\frac{1}{3}*0.1}{0.4667} = 0.0714$

7.14% probability that Benny was learning to ride a bike using the training wheels

b) Since Benny's mom knows Benny so well, she knows that the probability that he was using training wheels is 0.7, regular bike is 0.2, and unicycle is 0.1. What is the probability now that Benny fell while using the training wheels?

Similar as above, just some probabilities change.

Event A: Benny fell

Event B: Benny was using training wheels.

The probability that he was using training wheels is 0.7

This means that $P(B) = 0.7$

He did some research, and discovered that if he rides a bike with training wheels, the probability of falling is 0.1;

This means that $P(A|B) = 0.1$

Probability of falling:

0.7 of the time, he uses training wheels. With training wheels, the probability of falling is 0.1.

0.2 of the time, he uses the bike without training wheels. Without training wheels, the probability of falling is 0.5

0.1 of the time, he uses the unicycle, for which he has an 0.8 probability of falling. Then

$P(A) = 0.7*0.1 + 0.2*0.5 + 0.1*0.8 = 0.25$

So

$P(B|A) = \frac{0.7*0.1}{0.25} = 0.28$

28% probability that Benny was learning to ride a bike using the training wheels

7 0

4 years ago

Let n be a positive integer and define [n] to be the set of the first n positive integers. That is, [n] = {1, 2, 3, . . . , n}.

yaroslaw [1]

Answer: There are $2^{n-1}$ ways of doing this

Hi!

To solve this problem we can think in term of binary numbers. Let's start with an example:

n=5, A = {1, 2 ,3}, B = {4,5}

We can think of A as 11100, number 1 meaning "this element is in A" and number 0 meaning "this element is not in A"

And we can think of B as 00011.

Thinking like this, the empty set is 00000, and [n] =11111 (this is the case A=empty set, B=[n])

This representation is a 5 digit binary number. There are $2^5$ of these numbers. Each one of this is a possible selection of A and B. But there are repetitions: 11100 is the same selection as 00011. So we have to divide by two. The total number of ways of selecting A and B is the $2^{5-1} = 2^4$ .

This can be easily generalized to n bits.

6 0

4 years ago

Andrew is two years older than Beatrice, and Chris is three years younger than Beatrice.

In-s [12.5K]

Answer:

Beatrice's age is 34

Step-by-step explanation:

Beatruce = B

Andrew = B+2

Chris= B-3

B+(B+2) +(B-3 )= 67-B

3B-1 = 67-B

2B -1 = 67

2B= 68

B = 34

Beatrice is 34

Andrew is 36 (34+2)

Chris is 31 (34-3)

36+31 = 67

6 0

3 years ago

Renting a porch for the day there is a $50. Fee plus .50 per mile with a budget of $100. How many miles can you go

UkoKoshka [18]

Answer:2

Step-by-step explanation:

3 0

3 years ago

Determine the y-intercept and slope and then write the equation for this table.*

Novosadov [1.4K]

Answer:

The y-intercept is 15 and the slope is 5.5

y=5.5x+15

Step-by-step explanation:

4 0

3 years ago