1. Outcomes of the Experiment and Sample SpaceThe sample space consists of all possible pairs of cards drawn from the deck. Since there are 10 cards (Ace to 10), the number of ways to choose 2 cards from 10 is calculated as follows:
Total outcomes=(102)=10×92=45\text{Total outcomes} = \binom{10}{2} = \frac{10 \times 9}{2} = 45Total outcomes=(210)=210×9=45The sample space SSS can be represented as all combinations of the cards:
S={(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8),(1,9),(1,10),(2,3),(2,4),(2,5),(2,6),(2,7),(2,8),(2,9),(2,10),(3,4),(3,5),(3,6),(3,7),(3,8),(3,9),(3,10),(4,5),(4,6),(4,7),(4,8),(4,9),(4,10),(5,6),(5,7),(5,8),(5,9),(5,10),(6,7),(6,8),(6,9),(6,10),(7,8),(7,9),(7,10),(8,9),(8,10),(9,10)}S = \{(1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (1, 7), (1, 8), (1, 9), (1, 10), (2, 3), (2, 4), (2, 5), (2, 6), (2, 7), (2, 8), (2, 9), (2, 10), (3, 4), (3, 5), (3, 6), (3, 7), (3, 8), (3, 9), (3, 10), (4, 5), (4, 6), (4, 7), (4, 8), (4, 9), (4, 10), (5, 6), (5, 7), (5, 8), (5, 9), (5, 10), (6, 7), (6, 8), (6, 9), (6, 10), (7, 8), (7, 9), (7, 10), (8, 9), (8, 10), (9, 10)\}S={(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8),(1,9),(1,10),(2,3),(2,4),(2,5),(2,6),(2,7),(2,8),(2,9),(2,10),(3,4),(3,5),(3,6),(3,7),(3,8),(3,9),(3,10),(4,5),(4,6),(4,7),(4,8),(4,9),(4,10),(5,6),(5,7),(5,8),(5,9),(5,10),(6,7),(6,8),(6,9),(6,10),(7,8),(7,9),(7,10),(8,9),(8,10),(9,10)}2. Define Event AiA_iAiEvent AiA_iAi is defined as the set of outcomes for which the sum of the values of the cards equals iii. The possible sums range from 3 (Ace + Ace) to 19 (10 + 9). Below are the outcomes associated with each iii from 3 to 19.
- A3A_3A3: {(1, 2)}
- A4A_4A4: {(1, 3)}
- A5A_5A5: {(1, 4), (2, 3)}
- A6A_6A6: {(1, 5), (2, 4)}
- A7A_7A7: {(1, 6), (2, 5), (3, 4)}
- A8A_8A8: {(1, 7), (2, 6), (3, 5)}
- A9A_9A9: {(1, 8), (2, 7), (3, 6), (4, 5)}
- A10A_{10}A10: {(1, 9), (2, 8), (3, 7), (4, 6)}
- A11A_{11}A11: {(1, 10), (2, 9), (3, 8), (4, 7), (5, 6)}
- A12A_{12}A12: {(2, 10), (3, 9), (4, 8), (5, 7)}
- A13A_{13}A13: {(3, 10), (4, 9), (5, 8), (6, 7)}
- A14A_{14}A14: {(4, 10), (5, 9), (6, 8), (7, 7)}
- A15A_{15}A15: {(5, 10), (6, 9), (7, 8)}
- A16A_{16}A16: {(6, 10), (7, 9)}
- A17A_{17}A17: {(7, 10)}
- A18A_{18}A18: {(8, 10)}
- A19A_{19}A19: {(9, 10)}
3. Probability of Obtaining a Sum from 3 to 19The total number of outcomes is 45. We can calculate the probabilities P(Ai)P(A_i)P(Ai) for each iii from 3 to 19 by dividing the number of outcomes in each AiA_iAi by the total outcomes (45). Here are the probabilities for sums from 3 to 19:
- P(A3)=145P(A_3) = \frac{1}{45}P(A3)=451
- P(A4)=145P(A_4) = \frac{1}{45}P(A4)=451
- P(A5)=245P(A_5) = \frac{2}{45}P(A5)=452
- P(A6)=245P(A_6) = \frac{2}{45}P(A6)=452
- P(A7)=345=115P(A_7) = \frac{3}{45} = \frac{1}{15}P(A7)=453=151
- P(A8)=345=115P(A_8) = \frac{3}{45} = \frac{1}{15}P(A8)=453=151
- P(A9)=445P(A_9) = \frac{4}{45}P(A9)=454
- P(A10)=445P(A_{10}) = \frac{4}{45}P(A10)=454
- P(A11)=545=19P(A_{11}) = \frac{5}{45} = \frac{1}{9}P(A11)=455=91
- P(A12)=445P(A_{12}) = \frac{4}{45}P(A12)=454
- P(A13)=445P(A_{13}) = \frac{4}{45}P(A13)=454
- P(A14)=445P(A_{14}) = \frac{4}{45}P(A14)=454
- P(A15)=345=115P(A_{15}) = \frac{3}{45} = \frac{1}{15}P(A15)=453=151
- P(A16)=245P(A_{16}) = \frac{2}{45}P(A16)=452
- P(A17)=145P(A_{17}) = \frac{1}{45}P(A17)=451
- P(A18)=145P(A_{18}) = \frac{1}{45}P(A18)=451
- P(A19)=145P(A_{19}) = \frac{1}{45}P(A19)=451
4. Event BBB: Total Card Value is OddEvent BBB occurs when the sum of the two cards is odd. To determine P(B)P(B)P(B) and P(Bc)P(B^c)P(Bc):
- Pairs yielding odd sums:
The pairs that lead to an odd sum are:
- (1, 2) → 3
- (1, 4) → 5
- (1, 6) → 7
- (1, 8) → 9
- (1, 10) → 11
- (2, 3) → 5
- (2, 5) → 7
- (2, 7) → 9
- (2, 9) → 11
- (3, 4) → 7
- (3, 6) → 9
- (3, 8) → 11
- (4, 5) → 9
- (4, 7) → 11
- (5, 6) → 11
- (5, 8) → 13
- (6, 7) → 13
- (6, 9) → 15
- (7, 8) → 15
- (7, 10) → 17
- (8, 9) → 17
- (9, 10) → 19
Counting these outcomes, there are 23 outcomes resulting in odd sums.
Thus,
P(B)=2345P(B) = \frac{23}{45}P(B)=4523 P(Bc)=1−P(B)=2245P(B^c) = 1 – P(B) = \frac{22}{45}P(Bc)=1−P(B)=45225. Probability That the Sum of Two Cards is More Than 14To find the probability that the sum is more than 14, we list the pairs that result in sums greater than 14:
- A15A_{15}A15: {(5, 10), (6, 9), (7, 8)} → 3 outcomes
- A16A_{16}A16: {(6, 10), (7, 9)} → 2 outcomes
- A17A_{17}A17: {(7, 10)} → 1 outcome
- A18A_{18}A18: {(8, 10)} → 1 outcome
- A19A_{19}A19: {(9, 10)} → 1 outcome
Thus, the total number of outcomes for sums greater than 14 is:
3+2+1+1+1=83 + 2 + 1 + 1 + 1 = 83+2+1+1+1=8So, the probability that the sum is greater than 14 is:
P(sum>14)=P(\text{sum} > 14) =P(sum>14)=