In a standard deck of 52 playing cards, how many cards are black, that is, belong to the suits of clubs and spades?

Introduction / Context:
In many aptitude and reasoning tests, basic questions about a standard deck of playing cards are used to check memory, attention to detail, and comfort with simple counting. This question asks how many black cards are present when we consider a full standard deck of 52 playing cards. Knowing the structure of the deck is essential for later topics such as probability, permutations, and combinations.

Given Data / Assumptions:

• We have a standard deck with exactly 52 cards.
• The four suits are clubs, spades, hearts, and diamonds.
• Clubs and spades are black suits.
• Hearts and diamonds are red suits.
• Each suit contains the same number of cards.

Concept / Approach:
A standard playing card deck is evenly divided among four suits. Since the deck is uniform, each suit contains an equal share of the total cards. We use the fact that there are 52 cards and 4 suits to find the number of cards in each suit, and then we use the number of black suits to find the number of black cards in total. The problem is a straightforward application of division and multiplication, and it reinforces the idea of equal partitioning.

Step-by-Step Solution:
Step 1: Total number of cards in the deck is 52. Step 2: There are 4 suits in the deck, so cards per suit = 52 / 4 = 13. Step 3: Clubs and spades are the two black suits, so number of black suits = 2. Step 4: Number of black cards = cards per suit * number of black suits = 13 * 2. Step 5: Therefore, total black cards = 26.

Verification / Alternative check:
We can also think of the deck in terms of red and black halves. There are two red suits and two black suits. Because the deck is symmetrical, the total of 52 cards splits into 26 red cards and 26 black cards. This provides the same answer without explicitly calculating cards per suit first, and confirms that the result 26 is consistent with the symmetry of the deck.

Why Other Options Are Wrong:
13: This would be correct only if there were a single black suit. However, there are two black suits, so this undercounts by a factor of two.
39: This would correspond to three black suits out of four, which is not the structure of a standard deck.
52: This would mean every card is black, which is clearly incorrect because there are also red suits.
24: This suggests an incorrect calculation of cards per suit or an assumption of non uniform distribution; it does not match the standard structure of the deck.

Common Pitfalls:
A common mistake is to confuse the total number of cards with the number of cards of a specific color, or to forget that each suit has exactly 13 cards. Some learners also forget that there are exactly two black suits and two red suits, which leads to wrong multiplication factors. Carefully recalling the structure of the deck avoids these errors.

Final Answer:
The total number of black cards in a standard deck of 52 playing cards is 26.