First of all, as I told you a little while ago, here is the formula
that solves ALL probability problems. Memorize this:
Probability =
(number of different successful possibilities)
divided by
(total number of all possibilities).
How many cards are in the bag at the beginning ?
One with each letter of the alphabet. That's 26 .
So the total number of different possible results on the
first draw is 26 .
How many of them are 'successful' ?
A 'successful' card is one with a vowel (a, e, i, o, or u). That's 5 .
So the probability of pulling a vowel the first time is 5/26 .
Now, we're looking for the probability of pulling TWO vowels, without
replacing the first one. So what's the situation after the first one ?
If the first one is successful, then when you reach into the bag for
the second draw, there are only 25 total cards in the bag, and
only 4 vowels are left. So the probability of drawing a vowel the
second time is 4/25 .
The first one was 5/26 .
The second one was 4/25 .
The probability of both of them happening just like that is
(5/26) x (4/25) .
That looks like choice ' B ' to me.
