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secondary 4 | A Maths
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Candice
Candice

secondary 4 chevron_right A Maths chevron_right Singapore

Good evening! How do i solve this question?

Date Posted: 6 days ago
Views: 12

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Eric Nicholas K
Eric Nicholas K's answer
3618 answers (Tutor Details)
1st
Good evening Candice! Here are my workings for this question. We assume that the balls are drawn without replacement.
J
J
6 days ago
Alternative approaches :

P(None of the balls are red)

= 1 - P(at least 1 red)

= 1 - P(1 red) - P(2 red) - P(3 red)

= 1 - (4/11 x 7/10 x 6/9 x 3) - (4/11 x 3/10 x 7/9 x 3) - (4/11 x 3/10 x 2/9)

= 1 - 28/55 - 14/55 - 4/165

= 1 - 26/33
= 7/33

b)

answer already obtained in a)
Candice
Candice
6 days ago
Thank you i understand now!