4 votes 4 votes A train has 12 stations on it's route and it has to stopped at any 4 station, such that no two stations are consecutive. find number of possible way for choosing 4 station's? Combinatory combinatory engineering-mathematics + – hacker16 asked Jan 22, 2018 hacker16 2.1k views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
Best answer 2 votes 2 votes Total number of stations where train is stopping = 4 Total number of stations where train is not stopping = 8 So if we arrange all stations where train is not stopping linearly then there will be 9 positions to place 4 stations in between them we need to choose 4 stations out of 9 options = $\binom{9}{4}$ = 126 Mk Utkarsh answered Mar 1, 2018 selected Mar 2, 2018 by srestha Mk Utkarsh comment Share Follow See all 0 reply Please log in or register to add a comment.
0 votes 0 votes answer will be 126 ways sumit goyal 1 answered Jan 22, 2018 sumit goyal 1 comment Share Follow See all 5 Comments See all 5 5 Comments reply Show 2 previous comments sumit goyal 1 commented Jan 22, 2018 reply Follow Share https://math.stackexchange.com/questions/153030/counting-train-stops-using-combinatorics 126 is only answer , they used star bar ,where its given 630 , is it given in test series ? 0 votes 0 votes hacker16 commented Jan 22, 2018 reply Follow Share it's from some class notes. 0 votes 0 votes sumit goyal 1 commented Jan 22, 2018 reply Follow Share check link i provided 0 votes 0 votes Please log in or register to add a comment.