Given : A raffle offers a first prize of $1000, 2 second prizes of $300, and 20 third prizes of $10 each. If 20000 tickets are sold at 25 cents each, find the expected winnings for a person buying 1 ticket.

To find : What are the expected winnings?

Solution :

There are one first prize, 2 second prize and 20 third prizes.

Probability of getting first prize is $\frac{1}{20000}$

Probability of getting second prize is $\frac{2}{20000}$

Probability of getting third prize is $\frac{20}{20000}$

A raffle offers a first prize of $1000, 2 second prizes of $300, and 20 third prizes of $10 each.

So, The value of prizes is

$\frac{1}{20000}\times 1000+\frac{2}{20000}\times 300+\frac{20}{20000}\times 10$

If 20000 tickets are sold at 25 cents each i.e. $0.25.

Remaining tickets = 20000-1-2-20=19977

Probability of getting remaining tickets is $\frac{19977}{20000}$

The expected value is

$E=\frac{1}{20000}\times 1000+\frac{2}{20000}\times 300+\frac{20}{20000}\times 10-\frac{19977}{20000}\times 0.25$

$E=\frac{1000+600+200-4994.25}{20000}$

$E=\frac{-3194.25}{20000}$

$E=-0.159$

Therefore, The expected winnings for a person buying 1 ticket is -0.2.

3 0

3 years ago

Scott bought a pen and received change of $4.75 in 25 coins, all dimes and quarters. How many of each kind did he receive?

dangina [55]

Answer:

He received 10 dimes and 15 quarters.

Step-by-step explanation:

Dimes = $0.10

Quarters = $0.25

Variable x = dimes

Variable y = quarters

Create a pair of linear equations:

0.10x + 0.25y = 4.75

x + y = 25

Isolate any variable, using an equation of your choice:

x + y = 25

x = 25 - y

Plug in this new value of x into the other equation:

0.10(25 - y) + 0.25y = 4.75

Use the distributive property:

2.5 - 0.10y + 0.25y = 4.75

Combine like terms:

2.5 + 0.15y = 4.75

Isolate variable y:

0.15y = 2.25

y = 15

Plug in the value of y into any equation:

x + y = 25

x + 15 = 25

Isolate variable x:

x = 10

7 0

2 years ago

Plz help me. I forgot how to do this XD

nirvana33 [79]

This question has to do with making an approximation based on the diagram of the angle. Angle KLM is an obtuse angle meaning it is larger then 90° but is also less than 180°. The only choices that lie within this range are choices B and D. However, it is safe to assume that angle KLM is closer to 180° than to 90° based on the diagram, therefore the answer must be choice B.

I hope this helps.

5 0

3 years ago