The Odds

If the odds against an Event are a:b, the probability of that Event is...

• a/(a+b)

• a/(a-b)

• b/(a+b)

• b/(a-b)

If the probability of an Event E is a/b, the odds in favor of that Event are...

• (a+b)

• (b-a)

• (a+b)

• (a-b)

If the probability of an Event E is a/b, the odds against that Event are...

• (a+b)

• (a-b)

• (a+b)

• (b-a):a

In a deck of 52 playing cards what are the odds in favor of drawing a 2, 3, 4, or 5 of diamonds at random?

• 12:1

• 1:12

• 1:13

• 13:1

You roll a pair of fair dice. What are the odds against rolling a sum of 10? 

• 12:1

• 11:1

• 1:12

• 1:11

You roll a pair of fair dice. What are the odds in favor of rolling a sum of 12? 

• 1:36

• 1:35

• 1:18

• 1:12

Suppose this Accounting Monster really does generate random digits. What are the odds against Dilbert seeing this particular result for six digits?

• 999,999:1

• 60:1

• 59:1

• 1,000,000:1

If all the letters in the alphabet were placed in a bowl, what are the odds against pulling out an “A”, “H”, “R” or “X”? 

• 2:11

• 11:2

• 2:13

• 13:2

A trial consists of flipping a fair coin three times. What are the odds against the coin coming up heads each time?

• 7:1

• 6:1

• 8:1

• 9:1

The odds in favor of rain tomorrow are 6:11. What is the probability of rain tomorrow? Round to the nearest percent.

• 35%

• 55%

• 65%

• 85%