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Hager takes part in a chess competition - Junior Cycle Mathematics - Question 4 - 2018

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Hager takes part in a chess competition. In each game, she can win (W), draw (D), or lose (L). In each game she plays, each of these three outcomes is equally likely... show full transcript

Worked Solution & Example Answer:Hager takes part in a chess competition - Junior Cycle Mathematics - Question 4 - 2018

Step 1

Write down the probability that Hager wins her first game.

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Answer

The probability that Hager wins her first game can be calculated by observing that there are three equally likely outcomes: win (W), draw (D), or lose (L). Thus, the probability is:

P(Win) = rac{1}{3}

Step 2

Fill in the table below to show the 9 possible outcomes for Hager’s first two games.

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The possible outcomes for Hager's first two games can be outlined as follows:

Game 1Game 2
WW
WD
WL
DW
DD
DL
LW
LD
LL

Step 3

Find the probability that Hager wins Game 1 and loses Game 2.

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Answer

There are a total of 9 possible outcomes for two games. The specific outcome where Hager wins Game 1 and loses Game 2 is one of these outcomes. Therefore, we can find the probability as:

P(W, L) = rac{1}{9}

Step 4

Find the probability that Hager wins at least one of her first two games.

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Answer

To find the probability that Hager wins at least one game, we can alternatively calculate the probability that she does not win any games and subtract from 1. The only outcome where she does not win is the case where she either draws or loses both games. This results in:

The outcomes where she wins at least one game are:

  • WW
  • WL
  • WD
  • DW
  • DL
  • LW So, we have 6 successful outcomes for winning at least one game out of 9 total outcomes, leading to:

P(at \, least \, one) = 1 - P(none) = 1 - rac{3}{9} = rac{6}{9} = rac{2}{3}

Step 5

Work out the total number of different possible outcomes for her 3 games.

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Answer

Each game has 3 possible outcomes: W, D, or L. Therefore, for 3 games, the total number of different possible outcomes can be calculated as:

Totaloutcomes=3imes3imes3=27Total \, outcomes = 3 imes 3 imes 3 = 27

Step 6

Work out the probability that she doesn’t win any of her 3 games.

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Answer

The only outcomes where Hager does not win any of her games are when she either draws or loses all games. The outcomes are: DDD, DLL, DLD, LDD, LDL, LLD, LLL.

Thus, there are 8 favorable outcomes. The probability is given by:

P(doesn't \, win) = rac{8}{27}

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