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Vladimir [108]
2 years ago
7

Your friend asks if you would like to play a game of chance that uses a deck of cards and costs $1 to play. They say that if you

pick a random card and it is a black card, that you would win $2, if you choose a red card that is less than five you would win $10, and if you choose any other card you would lose $1. Would you agree to play this game with them?
What is the expected value of this game of chance? Help me please I’m begging you
Mathematics
1 answer:
gtnhenbr [62]2 years ago
7 0

Answer:

Expected value = 40/26 = 1.54 approximately

The player expects to win on average about $1.54 per game.

The positive expected value means it's a good idea to play the game.

============================================================

Further Explanation:

Let's label the three scenarios like so

  • scenario A: selecting a black card
  • scenario B: selecting a red card that is less than 5
  • scenario C: selecting anything that doesn't fit with the previous scenarios

The probability of scenario A happening is 1/2 because half the cards are black. Or you can notice that there are 26 black cards (13 spade + 13 club) out of 52 total, so 26/52 = 1/2. The net pay off for scenario A is 2-1 = 1 dollar because we have to account for the price to play the game.

-----------------

Now onto scenario B.

The cards that are less than five are: {A, 2, 3, 4}. I'm considering aces to be smaller than 2. There are 2 sets of these values to account for the two red suits (hearts and diamonds), meaning there are 4*2 = 8 such cards out of 52 total. Then note that 8/52 = 2/13. The probability of winning $10 is 2/13. Though the net pay off here is 10-1 = 9 dollars to account for the cost to play the game.

So far the fractions we found for scenarios A and B were: 1/2 and 2/13

Let's get each fraction to the same denominator

  • 1/2 = 13/26
  • 2/13 = 4/26

Then add them up

13/26 + 4/26 = 17/26

Next, subtract the value from 1

1 - (17/26) = 26/26 - 17/26 = 9/26

The fraction 9/26 represents the chances of getting anything other than scenario A or scenario B. The net pay off here is -1 to indicate you lose one dollar.

-----------------------------------

Here's a table to organize everything so far

\begin{array}{|c|c|c|}\cline{1-3}\text{Scenario} & \text{Probability} & \text{Net Payoff}\\ \cline{1-3}\text{A} & 1/2 & 1\\ \cline{1-3}\text{B} & 2/13 & 9\\ \cline{1-3}\text{C} & 9/26 & -1\\ \cline{1-3}\end{array}

What we do from here is multiply each probability with the corresponding net payoff. I'll write the results in the fourth column as shown below

\begin{array}{|c|c|c|c|}\cline{1-4}\text{Scenario} & \text{Probability} & \text{Net Payoff} & \text{Probability * Payoff}\\ \cline{1-4}\text{A} & 1/2 & 1 & 1/2\\ \cline{1-4}\text{B} & 2/13 & 9 & 18/13\\ \cline{1-4}\text{C} & 9/26 & -1 & -9/26\\ \cline{1-4}\end{array}

Then we add up the results of that fourth column to compute the expected value.

(1/2) + (18/13) + (-9/26)

13/26 + 36/26 - 9/26

(13+36-9)/26

40/26

1.538 approximately

This value rounds to 1.54

The expected value for the player is 1.54 which means they expect to win, on average, about $1.54 per game.

Therefore, this game is tilted in favor of the player and it's a good decision to play the game.

If the expected value was negative, then the player would lose money on average and the game wouldn't be a good idea to play (though the card dealer would be happy).

Having an expected value of 0 would indicate a mathematically fair game, as no side gains money nor do they lose money on average.

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If AP and PB are in a 1:2 ratio, it means that PB is twice AB.

So, AP must fit three times into AB, meaning that P must be at one third of the way between A and B.

6 0
3 years ago
Two cars, one going due east at 25 m / sec and the second going due south at 50/3 m / sec are traveling toward the intersection
valkas [14]

Answer:

30 m/s

Step-by-step explanation:

Let's say the distance from the first car to the intersection is x, and the distance from the second car to the intersection is y.

The distance between the cars can be found with Pythagorean theorem:

d² = x² + y²

Taking derivative with respect to time:

2d dd/dt = 2x dx/dt + 2y dy/dt

d dd/dt = x dx/dt + y dy/dt

We know that x = 200, dx/dt = -25, y = 150, and dy/dt = -50/3.

To find dd/dt, we still need to find d.

d² = x² + y²

d² = (200)² + (150)²

d = 250

Plugging everything in:

250 dd/dt = (200) (-25) + (150) (-50/3)

dd/dt = -30

The cars are approaching each other at a rate of 30 m/s at that instant.

4 0
2 years ago
suppose you know that over the last 10 years, the porbabiliy that your town would have at least one ma jor stor was 40%. describ
Anuta_ua [19.1K]

Answer:

The probability of a big storm is 40%.

Now, you can find a D10 (a die with 10 faces)

You can assign 4 numbers (0, 1, 2, 3) to the event "there is a major storm"

in this way, you have 40% of having a storm.

and the other 6 numbers (4, 5, 6, 7, 8, 9) to the event "there is not a major storm". This means that we have 60% of not having a storm.

now, when you roll the dice you can see if a year there will be a storm or not.

Now, you roll the dice 5 times (for the 5 years) and take note of the results and the number of storms in those 5 rolls.

Now do the same thing a bunch of times, at least 25 times.

Now, you recorded the results in each set of rolls, now see the number of sets that have at least years with storms.

Take that number and divide it by the total number of sets of data (in this case 25, for example)

The result is the probability that we are looking for.

6 0
3 years ago
Solve using the quadratic formula: 2x2-9x+12=0
marta [7]

Answer:

no solution

Step-by-step explanation:

For getting the nature of solution of the quadratic equation of the form:

ax² + bx + c = 0

We need to find Discriminant which is:

Discriminant (D) = b² - 4ac

  • If D < 0, there is no solution of equation.
  • If D = 0, there are two equal and real solution of equation
  • If D < 0, there are two real and distinct solution of equation

Here we have equation is:

2x² - 9x + 12 = 0

∴ a=2, b = -9, c = 12

⇒ D = 81 - 4 × 2 × 12 = -16 < 0

Hence, there is no solution of given equation.

5 0
3 years ago
Thirty- five out of sixty students preferred to eat their lunch at school rather going home in lunch break. Express the numbers
IceJOKER [234]

Answer:

0.583

Step-by-step explanation:

Use a caluclator

6 0
2 years ago
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