each of the numbers from 1 through 30 is written on a table tennis ball and placed in a wire cage. each of th enumbers 20 through 45 is written
on a table tennis ball and placed in a diffrent wire cage. one ball is chosen at random form each spinning cage. which of the following describe:
P(each is a 25)
a: 1/26
b: 9/30
c: 145/156
d: 1/780

Question

amistre64 · Answer

each of the numbers from 1 through 30 is written on a table tennis ball
          and placed in a wire cage. 

each of the numbers 20 through 45 is written on a table tennis ball
          and placed in a different wire cage. 

one ball is chosen at random form each spinning cage. 

which of the following describe:  P(each is a 25)

amistre64 · Answer

there are 30 chances and only one of them is a 25; so

1/30

in the second try there are 25 chances and only one of them is a 25

1/25

The chance that both are 25 is just multipliying these probs together

1/30 * 1/25

amistre64 · Answer

id say d, but I thats just a first glance

amistre64 · Answer

P(AndB) = P(A) * P(B)

amistre64 · Answer

1/750 is what I get .... so maybe theres a typo?

anonymous · Answer

The problem with your answer @amistre64, is that you are multiplying 1/30 with 1/25. There are 26 digits in the second wire case. So the answer would be 1/30 * 1/26, which would give you 1/780, which is D.

amistre64 · Answer

i was sooo close ;)  thnx