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artofspeed
hard probability question.. help plz?
want me to explain?
@kevinkeegan Please do
okay you have 4 choices tiles to use WWW WWB WBWetc... each will take up 3 slots and you have 10 slots only so we use 3 diff groups( groups as in WWW= 1grp, WBW=1grp an so on) first, taking up 9 slots, so the probability of arranging the 3 grps = 4X4X4 ; now we left with 1 last slot for the single white tile; and we can put the white tiles @ 4 different places( trying drawing out): so that gives us extra 4 different combos and therefore, total probability= 4X4X4X4
|dw:1335113090901:dw| arrow point to last slot for single white tile
I know the answer. http://ptri1.tripod.com/ptreal1r.gif See this picture of a pascal's triangle. Now see the row 2 and sum all the numbers of row 2 You get 4! See the row 10 and get the sum of all the numbers in row 10. You get the answer!
one thing to note: question did not state if the tiles can be reused, if cannot reuse, answer is 4X3X2X4
what about Parthkohli's way ?
pascal triangle does not work here becasue the tiles are in groups of 3
The question is about 10*1
pls read the question again
The final line, see it.
is they want us to use the 4 combo of WWW WWB WBW BWW then im right
Somebody please explain the question. It is confusing
they want u to use the combos to fill up the 10 slots
They're asking us the different colour patterns in a ten by one rectangle. There are 1024 such patterns. Try it on your own.
They're asking us about the number of patterns possible in this case.
last line : "using THESE TILES " and i suppose THESE TILES refer to the 4 different colour patterns
the tiles are not individual they come in sets
All right. You're right, I'm wrong. Okay?
|dw:1335113911913:dw|
@kevinkeegan, 'these tiles' actually refer to the 3 tiles in the picture
yep and the 3 tiles form the 4 colour patterns they giv WWW WBW BWW WWB
hey i think the ans is 385 plz check