Need quick help with these perms/coms questionscheck answers

  • Thread starter rock.freak667
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In summary, the cricket selection committee can be chosen in 65 ways to include at least one former batsman and one former bowler, and the total number of ways to select the committee is 70. The selection can also be simplified to 8C4 since these are the only ways to make the selection.
  • #1
rock.freak667
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[SOLVED] Need quick help with these perms/coms questions..check answers

Homework Statement


A cricket selection committee of 4 members is to be chosen from 5 former batsmen and 3 former bowlers.

In how many ways can this committee be selected so that the committee includes at least

1)One former batsman
2) One batsman and one bowler.


Homework Equations





The Attempt at a Solution



B=Batsman
b=bowlers

1)At least one former batsman

1B 3b=5C1*3C3=5
2B 2b=5C2*3C2=30
3B 1b=5C3*3C1=30
4B 0b=5C4=5

total=70 ways

2) no. of way to select without any restriction=8C4=70

so for at least one B and one b, it is 70-5=65


Also,since in part 1,those are the only ways to make the selection...does that mean I could have just said 8C4 instead of writing out all the ways?
 
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  • #2
Yes to all of the above, I think.
 
  • #3
well then...great...! I got confused since all of that was 8 marks
 

What are perms and coms?

Perms and coms are abbreviations for permutations and combinations, which are mathematical concepts used to calculate the number of possible arrangements or selections from a given set of items. Permutations refer to the number of ways to arrange a set of items in a specific order, while combinations refer to the number of ways to select a subset of items from a larger set.

Why is it important to understand perms and coms?

Perms and coms are important in various fields, including mathematics, statistics, and computer science. They are used to solve problems involving probability, counting, and optimization. Understanding perms and coms can also help in decision-making and problem-solving in daily life situations, such as planning events or organizing data.

What are some common applications of perms and coms?

Perms and coms have a wide range of applications, including in genetics, finance, and gaming. In genetics, perms and coms can be used to calculate the likelihood of certain genetic combinations or traits. In finance, they can be used to analyze the risks and returns of different investment portfolios. In gaming, they can be used to calculate the odds of winning a game or lottery.

What is the difference between permutations and combinations?

The main difference between permutations and combinations is the order of the selected items. Permutations take into account the order of the items, while combinations do not. For example, the permutations of the letters "ABC" would include "ABC", "ACB", "BAC", and so on, while the combinations would only include "ABC", "ACB", and "BAC".

How can I solve problems involving perms and coms?

To solve problems involving perms and coms, it is important to first identify whether the problem involves arranging items in a specific order (permutations) or selecting a subset of items (combinations). Then, you can use the relevant formulas or techniques to calculate the number of possible outcomes. It can also be helpful to break down the problem into smaller, simpler steps and to practice with sample problems to improve your understanding.

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