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- Choose 3 from 9, since the eldest boy is fixed. The number of different ways is

- If the eldest boy is excluded, we actually choose 4 boys from 9. The number of different ways is

- The number of all possible groups is

So the proportion of all possible groups containing the eldest boy is:

- Choose 3 from 9, since the eldest boy is fixed. The number of different ways is

- If the eldest boy is excluded, we actually choose 4 boys from 9. The number of different ways is

- The number of all possible groups is

So the proportion of all possible groups containing the eldest boy is:

We have all faced the scenario where we've had to decide between two choices such as: do you go to the cinema with friends or do you read this module? Sometimes when you can't make the decision you opt to let 'lady luck' decide.

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