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?

 

what kind of school do your kids go to? Wish my english schools asked questions like this when I was a kid instead of the simple bull**** kids in other countries learn at 4.

 

answer 0 eat the f,kin lot

 

I think that the probability of pulling a red then a blue is 7/20 X 8/19

Can't help with the second part.

 

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)

 

That's what I thought, but I lost confidence just before posting it.

 

whooooo!

thats a bit bloody complicated for 10 year olds?????

maybe she better get it wrong otherwise the teach will know she cheated

 

**** knows im colour blind!!!

 

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

 

Good point.

Why are we wasting our lives on this?

 

sweet was eaten so /19 is right..............kid off to school now, will report back with results at 3.30

 

This sounds suspiciously like a modern A level maths question

 

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.

 

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)