kids home work question
11 October 2006, 10:02 PM
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kids home work question
bag of sweets, 7 red, 5 green, 8 blue = 20 sweets
probability of pulling a red one = 7/20.....easy enough
probability of pulling a red then a blue = 7/20 X 8/20 = 56/400 = 7/50
probabiliy of pulling a red and blue in any order? ie- red then blue OR blue then red??????????????????? whats the answer?
probability of pulling a red one = 7/20.....easy enough
probability of pulling a red then a blue = 7/20 X 8/20 = 56/400 = 7/50
probabiliy of pulling a red and blue in any order? ie- red then blue OR blue then red??????????????????? whats the answer?
11 October 2006, 10:10 PM
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Originally Posted by The Snug Rhino
bag of sweets, 7 red, 5 green, 8 blue = 20 sweets
probability of pulling a red one = 7/20.....easy enough
probability of pulling a red then a blue = 7/20 X 8/20 = 56/400 = 7/50
probability of pulling a red and blue in any order? ie- red then blue OR blue then red??????????????????? whats the answer?
probability of pulling a red one = 7/20.....easy enough
probability of pulling a red then a blue = 7/20 X 8/20 = 56/400 = 7/50
probability of pulling a red and blue in any order? ie- red then blue OR blue then red??????????????????? whats the answer?
Can't help with the second part.
11 October 2006, 10:13 PM
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Originally Posted by TopBanana
probability of pulling a red then a blue = 7/20 X 8/19
probabiliy of pulling a red and blue in any order?
(Red then blue) + (blue then red)
(7/20 x 8/19) + (8/20 x 7/19)
probabiliy of pulling a red and blue in any order?
(Red then blue) + (blue then red)
(7/20 x 8/19) + (8/20 x 7/19)
That's what I thought, but I lost confidence just before posting it.
11 October 2006, 10:52 PM
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whooooo!
thats a bit bloody complicated for 10 year olds?????
maybe she better get it wrong otherwise the teach will know she cheated
thats a bit bloody complicated for 10 year olds?????
maybe she better get it wrong otherwise the teach will know she cheated
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11 October 2006, 11:38 PM
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Originally Posted by The Snug Rhino
bag of sweets, 7 red, 5 green, 8 blue = 20 sweets
probability of pulling a red one = 7/20.....easy enough
probability of pulling a red then a blue = 7/20 X 8/20 = 56/400 = 7/50
probabiliy of pulling a red and blue in any order? ie- red then blue OR blue then red??????????????????? whats the answer?
probability of pulling a red one = 7/20.....easy enough
probability of pulling a red then a blue = 7/20 X 8/20 = 56/400 = 7/50
probabiliy of pulling a red and blue in any order? ie- red then blue OR blue then red??????????????????? whats the answer?
11 October 2006, 11:42 PM
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Originally Posted by boxst
Hello
There isn't really enough information, as you don't know whether the sweets are put back or not (hence the 19 in bold above).
Steve
There isn't really enough information, as you don't know whether the sweets are put back or not (hence the 19 in bold above).
Steve
Why are we wasting our lives on this?
12 October 2006, 08:13 AM
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sweet was eaten so /19 is right..............kid off to school now, will report back with results at 3.30
12 October 2006, 09:22 AM
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With any luck this question was to flush out the irresponsible pushy parents who are more concerned about boasting to each other about their foetus' maths results than making sure the brats actually understand the working behind it.
A letter should be on it's way to social services.
A letter should be on it's way to social services.
12 October 2006, 02:22 PM
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i have an idea it was all about getting them to mutiply fractions to establish probability - i have a hunch they were NOT expecting them to reduce the 2nd count to 19 to allow for the eaten sweet.
be interesting to see when she gets home (still think its OTT for 10 year olds)
be interesting to see when she gets home (still think its OTT for 10 year olds)
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