CBSE2026Class Class 10 · Mathematics4 Marks · Long✅ Verified
CASE STUDY : A group of friends wanted to play cards with two identical packs together. While shuffling the cards, three cards are dropped. Rest of the cards are shuffled and one card is drawn at random. Assuming that the dropped cards were a queen of hearts, a ten of spades and an ace of clubs, answer the following questions :
(i) Find the probability that the drawn card is a face card. [1]
(ii) Find the probability that the drawn card is either a king or a queen. [1]
(iii) (a) Do you think that the probability of getting a queen was higher if none of the cards were dropped ? Justify your answer. [2]
OR
(iii) (b) Find the probability that the drawn card is a jack. Compare it with the probability when none of the cards were dropped. In which case is the probability of getting a jack higher ? [2]
✅ Answer & Solution
Step 0: Two identical packs together contain $2 \times 52 = 104$ cards.
Three cards are dropped, so the number of remaining cards $= 104 - 3 = 101$.
(i) Probability of a face card
Step 1: Face cards (King, Queen, Jack) in one pack $= 12$, so in two packs $= 24$.
Step 2: One face card (queen of hearts) was dropped, so face cards left $= 24 - 1 = 23$.
Step 3: $$P(\text{face card}) = \frac{23}{101}$$
(ii) Probability of a king or a queen
Step 4: Kings in two packs $= 8$ (none dropped). Queens in two packs $= 8$, one dropped, so $7$ left.
Step 5: Favourable outcomes $= 8 + 7 = 15$.
$$P(\text{king or queen}) = \frac{15}{101}$$
(iii) (a) Comparing the probability of a queen
Step 6: After dropping : $$P_1(\text{queen}) = \frac{7}{101} \approx 0{\cdot}0693$$
Step 7: If no card were dropped : $$P_2(\text{queen}) = \frac{8}{104} = \frac{1}{13} \approx 0{\cdot}0769$$
Step 8: Since $\dfrac{8}{104} > \dfrac{7}{101}$, YES, the probability of getting a queen would have been HIGHER if none of the cards were dropped, because one queen was among the dropped cards.
OR
(iii) (b) Probability of a jack
Step 9: No jack was dropped, so jacks left $= 8$ out of $101$ cards.
$$P_1(\text{jack}) = \frac{8}{101}$$
Step 10: If no card were dropped : $$P_2(\text{jack}) = \frac{8}{104} = \frac{1}{13}$$
Step 11: Since the numerators are equal and $101 \frac{8}{104}$$
Hence the probability of getting a jack is HIGHER in the case when the three cards were dropped.