DMD to Be

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A roulette wheel consists of 38 slots. 36 of these are numbered 1 through 36 and colored red or black so that there are nine red even-numbered slots, nine black odd-numbered slots, etc. These slots occurs with equal probability. The two slots marked 0 or 00 are each three times as likely to occur as any one the other 36. What is the pprobablitliy that a red even number, a red 23, or a 00 will occur on one roll of the wheel?

A. 2/7
B. 5/18
C. 13/38
D. 13/42
E. 3/10

The correct answer is D. I worked it out like so and got C.

9/38 (chance of red even number) + 1/38 (chance of red 23) + 3/38 (chance of 00) = 13/38.

Probably some silly mistake. Help, please.
 

ConfusedOne

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DMD to Be said:
A roulette wheel consists of 38 slots. 36 of these are numbered 1 through 36 and colored red or black so that there are nine red even-numbered slots, nine black odd-numbered slots, etc. These slots occurs with equal probability. The two slots marked 0 or 00 are each three times as likely to occur as any one the other 36. What is the pprobablitliy that a red even number, a red 23, or a 00 will occur on one roll of the wheel?

A. 2/7
B. 5/18
C. 13/38
D. 13/42
E. 3/10

The correct answer is D. I worked it out like so and got C.

9/38 (chance of red even number) + 1/38 (chance of red 23) + 3/38 (chance of 00) = 13/38.

Probably some silly mistake. Help, please.
What a weird roulette wheel. So i guess since the 00 and the 0 slots are three times as likely to occur as a 'regular' one, you can count each of them as 3 'regular' slots, so there are actually 42 regular slots ? :confused:
 

Envision

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DMD to Be said:
A roulette wheel consists of 38 slots. 36 of these are numbered 1 through 36 and colored red or black so that there are nine red even-numbered slots, nine black odd-numbered slots, etc. These slots occurs with equal probability. The two slots marked 0 or 00 are each three times as likely to occur as any one the other 36. What is the pprobablitliy that a red even number, a red 23, or a 00 will occur on one roll of the wheel?

A. 2/7
B. 5/18
C. 13/38
D. 13/42
E. 3/10

The correct answer is D. I worked it out like so and got C.

9/38 (chance of red even number) + 1/38 (chance of red 23) + 3/38 (chance of 00) = 13/38.

Probably some silly mistake. Help, please.
your missing the "3 times more likely part" thus, there is 36 equvilent spots, and 0 and 00 counts for 3 equvilence each. this means its out of 42 instead of 38. so 9/42 (red even), 1/42 (red 23), and 3/42 (00) = 13/42
 
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Jan 6, 2013
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I have a question, it states that there are 9 red even slots, doesn't that mean that the only red ones are even numbers? Then how can the question ask for a red 23?:confused:
 

chill45

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Jan 18, 2012
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I have a question, it states that there are 9 red even slots, doesn't that mean that the only red ones are even numbers? Then how can the question ask for a red 23?:confused:
No, there are 9 red even, 9 red odd, 9 black even, and 9 black odd on a roulette table (36 total plus the 0 and 00 which are both green on the wheel). Trust me I just lost $300 at a roulette table two nights ago lol
 
Jan 6, 2013
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omg thank you, that's what I get for not ever going to a casino, the things I must do to get into dental school! lol
 
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