Difference between revisions of "2005 AMC 8 Problems/Problem 24"

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hI kIDS i am bob AND I SHALL EAT YOU. NEVETR COME AND TRY TO HURT ME. I AM THE GOD OF HACKING
 
hI kIDS i am bob AND I SHALL EAT YOU. NEVETR COME AND TRY TO HURT ME. I AM THE GOD OF HACKING
 
YOur butt smells
 
YOur butt smells
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First we can start at 200 and work our way down we want to do /2 the most so if we come across an odd number we just subtract 1!  So 200/2=100, 100/2=50, 50/2=25, 25-1=24, 24/2=12, 12/2=6, 6/2=3, 3-1=2, and 2/2=1. We made our way back to 1 but since it is the amount of times the button is pressed than the answer should be B 9
  
 
==See Also==
 
==See Also==
 
{{AMC8 box|year=2005|num-b=23|num-a=25}}
 
{{AMC8 box|year=2005|num-b=23|num-a=25}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Revision as of 14:28, 28 September 2020

Problem

A certain calculator has only two keys [+1] and [x2]. When you press one of the keys, the calculator automatically displays the result. For instance, if the calculator originally displayed "9" and you pressed [+1], it would display "10." If you then pressed [x2], it would display "20." Starting with the display "1," what is the fewest number of keystrokes you would need to reach "200"?

$\textbf{(A)}\ 8\qquad\textbf{(B)}\ 9\qquad\textbf{(C)}\ 10\qquad\textbf{(D)}\ 11\qquad\textbf{(E)}\ 12$

Solution

hI kIDS i am bob AND I SHALL EAT YOU. NEVETR COME AND TRY TO HURT ME. I AM THE GOD OF HACKING YOur butt smells



First we can start at 200 and work our way down we want to do /2 the most so if we come across an odd number we just subtract 1! So 200/2=100, 100/2=50, 50/2=25, 25-1=24, 24/2=12, 12/2=6, 6/2=3, 3-1=2, and 2/2=1. We made our way back to 1 but since it is the amount of times the button is pressed than the answer should be B 9

See Also

2005 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 23
Followed by
Problem 25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AJHSME/AMC 8 Problems and Solutions

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