<p>What is the sum of the digits of the decimal form of the product <img alt="$2^{1999}\cdot 5^{2001}$" height="15" src="https://latex.artofproblemsolving.com/e/a/4/ea479cc13e3907061052f42c91341a9855378561.png" width="83" />?</p> <p><img alt="$\textbf{(A)}\ 2\qquad \textbf{(B)}\ 4 \qquad \textbf{(C)}\ 5 \qquad \textbf{(D)}\ 7\qquad \textbf{(E)}\ 10$" height="18" src="https://latex.artofproblemsolving.com/8/4/8/848c2915f8132ae8d481f10a1ba6eb9a1333e161.png" width="360" /></p>

Question No: 473

What is the sum of the digits of the decimal form of the product $2^{1999}\cdot 5^{2001}$ ?

$\textbf{(A)}\ 2\qquad \textbf{(B)}\ 4 \qquad \textbf{(C)}\ 5 \qquad \textbf{(D)}\ 7\qquad \textbf{(E)}\ 10$

Editorial

Tags: Number Theory

Question Details