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Ben has to choose three subjects to study - Leaving Cert Mathematics - Question 3(b) - 2022

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Question 3(b)

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Ben has to choose three subjects to study. He must pick one subject from each of these three groups: Group A (3 subjects) French Spanish German Group B (4 subjec... show full transcript

Worked Solution & Example Answer:Ben has to choose three subjects to study - Leaving Cert Mathematics - Question 3(b) - 2022

Step 1

How many different choices of three subjects can Ben make, picking one from each group?

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Answer

To find the total number of different choices of subjects Ben can make, we will multiply the number of options available in each group together.

Group A has 3 subjects, Group B has 4 subjects, and Group C has 5 subjects. Therefore, the total choices can be calculated as:

extTotalChoices=extChoicesfromGroupAimesextChoicesfromGroupBimesextChoicesfromGroupC extTotalChoices=3imes4imes5=60 ext{Total Choices} = ext{Choices from Group A} imes ext{Choices from Group B} imes ext{Choices from Group C} \ ext{Total Choices} = 3 imes 4 imes 5 = 60

Thus, Ben can make 60 different combinations of subjects.

Step 2

Which group should the extra subject be added to, in order to make the number of different choices of three subjects that Ben can make as large as possible? Justify your answer.

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Answer

To determine the optimal group to add an extra subject, we will calculate the new total choices for each group:

  • Group A: Adding one subject would increase the choices to 4:

    extTotalChoices=4imes4imes5=80 ext{Total Choices} = 4 imes 4 imes 5 = 80
  • Group B: Adding one subject would increase the choices to 5:

    extTotalChoices=3imes5imes5=75 ext{Total Choices} = 3 imes 5 imes 5 = 75
  • Group C: Adding one subject would increase the choices to 6:

    extTotalChoices=3imes4imes6=72 ext{Total Choices} = 3 imes 4 imes 6 = 72

Comparing these calculations, the biggest increase in choices occurs when the extra subject is added to Group A, resulting in 80 choices. Therefore, the school should add the extra subject to Group A to maximize Ben's options.

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