1. card problem

I would appreciate if you can solve this problem.

Each of the cards shown below has a number on one side and a letter on the other. How many of the cards must be turned over to prove the correctness of this statement for these cards: "If a card has a vowel on one side, then it has a prime number on the other side" ?

[ A ] [ B ] [ C ] [ 3 ] [ 4 ] [ 5 ]

2. Originally Posted by chil2e
I would appreciate if you can solve this problem.
Each of the cards shown below has a number on one side and a letter on the other. How many of the cards must be turned over to prove the correctness of this statement for these cards: "If a card has a vowel on one side, then it has a prime number on the other side" ?
[ A ] [ B ] [ C ] [ 3 ] [ 4 ] [ 5 ]
Why don't you solve it for yourself.

I will play the part of the 'back-of-the-book".

3. Hello, chil2e!

The problem is not clearly stated.

Each of the cards shown below has a number on one side and a letter on the other.
How many of the cards must be turned over to prove the correctness of this statement:
"If a card has a vowel on one side, then it has a prime number on the other side" ?

. . $\displaystyle [\,A\,]\quad[\,B\,]\quad[\,C\,]\quad[\;3\;]\quad[\;4\;]\quad[\;5\;]$

The cards are to be "turned over".

Does this mean each card has one side already visible?

If so, which sides are visible?
. . The letters? .the numbers? .a random mix?