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Five cards – the ten, jack, queen, king and ace of diamonds are well-shuffled with their faces downwards. One card is then picked up at random. (a) What is the probability that the drawn card is the queen?I. 1/2 II. 1/3 III. 1/4 IV. 1/5(b) If the queen is drawn and put aside and a second card is drawn. What is the probability that the 2nd card is an ace? I. 1/2 II. 1/3 III. 1/4 IV. 1/5 (c) What is the probability that the second card is queen?I. 1/2 II. 1/3 III. 1/4 IV. None(d) From five cards, two cards are drawn. Find the probability that the drawn cards are an ace and ten?I. 1/5II. 2/5 III. 1/25 IV. None(e) The probability that an ordinary year has 53 Mondays is : I. 1/7 II. 53/365 III. 1/365 IV. None |
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Answer» We have five cards – ten, jack, queen, king and ace of diamonds. Total cards = n(S) = 5. (a) Option (iv) Total queen cards in given set of cards n(E1) = 1. ∴ Probability that drawn card is a queen = \(\frac{n(E_1)}{ n(S)}\) = \(\frac{1}{5}\). Hence, Option (iv) is correct. (b) Option (iii) If the queen is drawn and put aside. Then total number of remaining cards = n(S') = 4. And total ace cards in remaining set of cards = n(E1) = 1. ∴ The probability that 2nd card is an ace = \(\frac{n(E_1)}{ n(S')}\) = \(\frac{1}{4}\) . Hence, Option (iii) is correct. (c) Option (iv) Total queen cards in the remaining set of cards = n(E3) = 0. ∴ The probability that 2nd card is queen card = \(\frac{n(E_3)}{ n(S') }\) = \(\frac{0}{4}\) = 0. Hence, Option (iv) is correct. (d) Option (iv) From five cards, Two cards are drawn. Let \(E'_4\) = Event that first card is ten and second card is ace card. \(E''_4\) = Event that first card is ace card and second card is ten card. S4 = total possible outcomes in drawing two cards = 5 × 4 = 20. ∴ Probability that drawn card are an ace card and ten card = P(\(E'_4\)) + P(\(E''_4\)) = \(\frac{1}{5\times 4}\) + \(\frac{1}{5\times 4}\) = \(\frac{2}{20}\) = \(\frac{1}{10}\) Hence, The correct answer is option (iv). (e) Option (i) In an ordinary year, total day = 365 = 52 weeks and 1 day. Hence, There will be 52 Mondays for sure. So, In ordinary year there will be 52 Mondays and 1 day will be left This one day could be a Monday or Tuesday or Wednesday or Thursday or Friday or Saturday or Sunday. Hence, Total possible outcomes = 7 But favorable outcome = 1. ∴ Probability of getting 53 Mondays = \(\frac{1}{7}\). Hence, Option (i) is correct. |
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