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# s1 help needed watch

1. There are 14 girls and 11 boys in a class. A quiz team of 5 students is to be chosen from the class.
(i) How many different teams are possible? [2]
(ii) If the team must include 3 girls and 2 boys, ﬁnd how many different teams are possible. [3]

on question one i know its something to do with 25. i tried 25*24*23*22*21 but it didnt give me the right answer. please can somebody explain what to do
2. help
3. help me its due for tomoz
4. (Original post by iamgreatness)
There are 14 girls and 11 boys in a class. A quiz team of 5 students is to be chosen from the class.
(i) How many different teams are possible? [2]
(ii) If the team must include 3 girls and 2 boys, ﬁnd how many different teams are possible. [3]

on question one i know its something to do with 25. i tried 25*24*23*22*21 but it didnt give me the right answer. please can somebody explain what to do
I'm assuming you've been introduced to permutations and combinations? I did this quite a while back now, but:

i) You correctly note there are 25 people in total and you need 5 people to fill the team. So how would you go about using combinations to find all of the different ways of selecting 5 from 25 people?

ii) Now you have to break the problem down into the fact that in every team you must choose 3 girls from 14 and 2 boys from 11. When you've calculated the number of ways each of these is possible you need to consider that any selection of boys could be matched with any selection of girls.

Hope that helps, they're really quite simple calculations to plug into your calculator so I didn't want to write them down just out of the blue. Let me know if doesn't help.
5. (Original post by Outsanity)
I'm assuming you've been introduced to permutations and combinations? I did this quite a while back now, but:

i) You correctly note there are 25 people in total and you need 5 people to fill the team. So how would you go about using combinations to find all of the different ways of selecting 5 from 25 people?

ii) Now you have to break the problem down into the fact that in every team you must choose 3 girls from 14 and 2 boys from 11. When you've calculated the number of ways each of these is possible you need to consider that any selection of boys could be matched with any selection of girls.

Hope that helps, they're really quite simple calculations to plug into your calculator so I didn't want to write them down just out of the blue. Let me know if doesn't help.
dude i just watched the exam solutions guy

i swear for the first one its just 25*24*23*22*21? but that doesnt give me the answer..
6. (Original post by Outsanity)
I'm assuming you've been introduced to permutations and combinations? I did this quite a while back now, but:

i) You correctly note there are 25 people in total and you need 5 people to fill the team. So how would you go about using combinations to find all of the different ways of selecting 5 from 25 people?

ii) Now you have to break the problem down into the fact that in every team you must choose 3 girls from 14 and 2 boys from 11. When you've calculated the number of ways each of these is possible you need to consider that any selection of boys could be matched with any selection of girls.

Hope that helps, they're really quite simple calculations to plug into your calculator so I didn't want to write them down just out of the blue. Let me know if doesn't help.
oh ok i did the ncr thing and got the answer lol
7. (Original post by Outsanity)
I'm assuming you've been introduced to permutations and combinations? I did this quite a while back now, but:

i) You correctly note there are 25 people in total and you need 5 people to fill the team. So how would you go about using combinations to find all of the different ways of selecting 5 from 25 people?

ii) Now you have to break the problem down into the fact that in every team you must choose 3 girls from 14 and 2 boys from 11. When you've calculated the number of ways each of these is possible you need to consider that any selection of boys could be matched with any selection of girls.

Hope that helps, they're really quite simple calculations to plug into your calculator so I didn't want to write them down just out of the blue. Let me know if doesn't help.
i dont understand though surely 25*24*23*22*21 should give me the same as 25c5? and on exam solutions hes using npr but u get a different number for that
8. (Original post by Outsanity)
I'm assuming you've been introduced to permutations and combinations? I did this quite a while back now, but:

i) You correctly note there are 25 people in total and you need 5 people to fill the team. So how would you go about using combinations to find all of the different ways of selecting 5 from 25 people?

ii) Now you have to break the problem down into the fact that in every team you must choose 3 girls from 14 and 2 boys from 11. When you've calculated the number of ways each of these is possible you need to consider that any selection of boys could be matched with any selection of girls.

Hope that helps, they're really quite simple calculations to plug into your calculator so I didn't want to write them down just out of the blue. Let me know if doesn't help.
thanks for second i did 14c3 times 11c2 thnx for help

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