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Maths Puzzle
3 blocks are chosen randomly on a chessboard. What is the probability that they are in the same diagonal?
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- there r 16/64 chances of choosing 1st blok
as there are 16 diagonal box and 64 in total.
2nd blok is taken from the diagonal which is selected in the 1st case.
n there are 8 bloks in a diagonal. n frm these 8 bloks we hav alredy taken 1 blok in case1.
we r nw left wd 7 blocks.
n 2nd wil b chosen frm 63 bloks because 1 has alredy gone.
so therefore prob of block 2= 7/63
||ly 3rd block prob= 6/62
(6 bcoz 2 hav alredy chosen, n 62 bcoz we r left wd 62 bloks in total after the cas1 n 2.)
first blok: 16/64= 1/4
2nd blok: 7/63=1/9 (without replacement)
3rd blok: 6/62
prob= 1/4 * 1/9 * 6/62= 1/372 - 12 years agoHelpfull: Yes(19) No(5)
- (16/64)*(7/63)*(6/62) = 1/372
- 15 years agoHelpfull: Yes(12) No(7)
- there are 8 blocks in each diagonal.
so if we are asked to choose 3 blocks to be on same diagonal,it can be chosen in 8C3 ways.
total number of blocks in a chessboard is 64,so 3 blocks can be chosen from 64 blocks in 64C3 ways.
so,probability 8C3/64C3=1/372 - 11 years agoHelpfull: Yes(5) No(2)
- there are 14 possibility of 7 adjacent boxes.
no of boxes in each line =8
so 8*14=112*2/64c3=1/372 - 9 years agoHelpfull: Yes(0) No(0)
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