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2007 iTest Problems/Problem 11

Revision as of 21:52, 4 October 2014 by Timneh (talk | contribs) (Created page with "== Problem 11 == Consider the "tower of power" <math>2^{2^{2^{\cdot^{\cdot^\cdot^{2}}}}}</math>, where there are 2007 twos including the base. What is the last (units digit) of t...")
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Problem 11

Consider the "tower of power" $2^{2^{2^{\cdot^{\cdot^\cdot^{2}}}}}$ (Error compiling LaTeX. Unknown error_msg), where there are 2007 twos including the base. What is the last (units digit) of this number?

$\text{(A) }0\qquad \text{(B) }1\qquad \text{(C) }2\qquad \text{(D) }3\qquad \text{(E) }4\qquad \text{(F) }5\qquad \text{(G) }6\qquad \text{(H) }7\qquad \text{(I) }8\qquad \text{(J) }9\qquad \text{(K) }2007\qquad$

Solution

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