# what is the probability that the next two cards selected will be....

• Dec 11th 2011, 07:57 AM
slapmaxwell1
what is the probability that the next two cards selected will be....
ok lets try another probability problem....

i have 3 cards, the first has a 3 on it, the second has a 5 on it and the third has a 9 on it.

the question states that the 3 cards were taken from a box of 10 cards, each with a different integer on it from 1 to 10. what is the probability that the next two cards selected from the box will have both even integers on it?

ok so there are 7 cards remaining, each with 1, 2,4, 6, 7, 8 and 10.

so on our first try we get 5/7

on our second try we get 4/6 or 2/3?

so 5/7 times 2/3 =10/21

is this right?
• Dec 11th 2011, 08:00 AM
e^(i*pi)
Re: what is the probability that the next two cards selected will be....
Quote:

Originally Posted by slapmaxwell1
ok lets try another probability problem....

i have 3 cards, the first has a 3 on it, the second has a 5 on it and the third has a 9 on it.

the question states that the 3 cards were taken from a box of 10 cards, each with a different integer on it from 1 to 10. what is the probability that the next two cards selected from the box will have both even integers on it?

ok so there are 7 cards remaining, each with 1, 2,4, 6, 7, 8 and 10.

so on our first try we get 5/7

on our second try we get 4/6 or 2/3?

so 5/7 times 2/3 =10/21

is this right?

Yes, that's right
• Dec 11th 2011, 08:03 AM
slapmaxwell1
Re: what is the probability that the next two cards selected will be....
Quote:

Originally Posted by e^(i*pi)
Yes, that's right

ok so why is it necessary to multiply? im still not getting that part?
• Dec 11th 2011, 08:14 AM
slapmaxwell1
Re: what is the probability that the next two cards selected will be....
this problem was taken from Dr. Chung's SAT Math pg 52