Difference between revisions of "1995 AHSME Problems/Problem 15"

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==Solution==
 
==Solution==
It moves 1, 2, 4, 1, 2, 4, etc. Thus after 1995=3*665 jumps, it will be on point 4 <math>\Rightarrow \mathrm{(D)}</math>.
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It moves in a cycle that goes <math>\{1, 2, 4, 1, 2, 4...\}</math>. The cycle has a period of <math>3</math>.
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Thus, after <math>1995=3*665</math> jumps, it will be on point <math>4</math> <math>\Rightarrow \mathrm{(D)}</math>.
  
 
==See also==
 
==See also==

Revision as of 16:43, 18 August 2011

Problem

Five points on a circle are numbered 1,2,3,4, and 5 in clockwise order. A bug jumps in a clockwise direction from one point to another around the circle; if it is on an odd-numbered point, it moves one point, and if it is on an even-numbered point, it moves two points. If the bug begins on point 5, after 1995 jumps it will be on point

$\mathrm{(A) \ 1 } \qquad \mathrm{(B) \ 2 } \qquad \mathrm{(C) \ 3 } \qquad \mathrm{(D) \ 4 } \qquad \mathrm{(E) \ 5 }$

Solution

It moves in a cycle that goes $\{1, 2, 4, 1, 2, 4...\}$. The cycle has a period of $3$.

Thus, after $1995=3*665$ jumps, it will be on point $4$ $\Rightarrow \mathrm{(D)}$.

See also

1995 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 14
Followed by
Problem 16
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All AHSME Problems and Solutions