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junior college 1 | H2 Maths
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Elaine
Elaine

junior college 1 chevron_right H2 Maths chevron_right Singapore

Help please thank you!

Date Posted: 4 years ago
Views: 325

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Boy Mow Chau
Boy Mow Chau's answer
316 answers (Tutor Details)
1st
Not 100% sure about this one :(
Boy Mow Chau
Boy Mow Chau
4 years ago
To check if answer is correct, one method is to make an actual list of all the possible combinations.

For class size of 17 and 20, the total ways is too large to list out all the possible combinations.

Have tried with a smaller class size of 7, splitted into 1 group of 3 and 2 groups of 2.

Using the same method of calculation,
total ways =(7C3 x 4C2 x 2C2)/2!
=105
By actual listing out all the possible combinations, have found that it exactly corresponds to the total ways found by calculation.

Therefore, now more confident that the method of calculation used here, is correct.
Elaine
Elaine
4 years ago
Thank you!