2010 AMC 8 Problem 25
Attempt Problem 25 of the 2010 AMC 8 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2010 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
25.
Every day at school, Jo climbs a flight of stairs. Jo can take the stairs or at a time. For example, Jo could climb then then In how many ways can Jo climb the stairs?
Answer: E
Small hint:
The first step can be , , or stairs, giving a recurrence.
Big hint:
Let be the number of ways to climb stairs.
Solution:
Let be the number of ways to climb stairs. For , the first step can be , , or stairs, so .
We have , , and . Therefore , , and .
Thus, the answer is E .
Problem 25 in other years
- 1985 AMC 8
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