0
$\begingroup$

I understand the concept, but I don't understand what operation I should use to calculate the paths.

It is a (5,3) grid and the rules state: How many paths are there from (0,0) to (5,3). Paths can go UP or RIGHT, but not LEFT or DOWN.

When I look it, I see that a path from start to finish, is exactly 8 "moves".

My question is, is this the answer? or is the question asking me what are the total number of "8 paths" that I could come up with. The wording seems a bit vague

$\endgroup$
  • 2
    $\begingroup$ The question is to find the total number of "8 paths" that you could come up with. $\endgroup$ – астон вілла олоф мэллбэрг Oct 14 '17 at 1:33
  • $\begingroup$ I have taken the liberty to shorten your title: in particular, don't use "need help" in a title. Everybody on this site could do that ... without any "added value". $\endgroup$ – Jean Marie Oct 15 '17 at 21:04
6
$\begingroup$

Going from $(0,0)$ to $(5,3)$ will always require 8 moves, with $5$ being right moves, and $3$ being up moves. One such example is the sequence $UUURRRRR$.

How many ways can you arrange this sequence? You can think about it as "how many ways can you change 3 $R$'s to $U$'s in the sequence $RRRRRRRR$". If you swap the different $R$'s around, will the sequence still be the same?

$\endgroup$
  • $\begingroup$ Does that mean I should apply C(8,3) ? or possibly convert to binary and solve it that way? I've only been in this class for two weeks, so it's hard to grasp which operation I should be using $\endgroup$ – Johnny James Oct 14 '17 at 1:48
  • $\begingroup$ Yes, that's correct. You should use combinations here because the 3 $R$'s are not different from each other. $\endgroup$ – Toby Mak Oct 14 '17 at 1:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.