Ways of walking up a flight of 10 stairs

[nelsonling]

How many ways are there of walking up a flight of 10 stairs if you take either one or three stairs with each step ?

(A) 15 (B) 20 (C) 24 (D) 28 (E) 40

 

[Deleted member 4993]

How many ways are there of walking up a flight of 10 stairs if you take either one or three stairs with each step ?

(A) 15 (B) 20 (C) 24 (D) 28 (E) 40

You have posted several problems - without showing any work.

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Please show some work - or share your thoughts regarding possible ways to attack the problem.

This problem is looking for ways you can place 3's and 1's so that those add upto 10.

to start off you can have three 3's and one 1. Those can be arranged as

1333
3133
3313
3331

Next set can be two 3's and four 1's. Now arrange those....

Next set can be one 3 and seven 1's. Now arrange those....