2008 Gauss 8 Problem 18

Andrea has finished the third day of a six-day canoe trip. If she has completed \frac{3}{7} of the trip's total distance of 168 km, how many km per day must she average for the remainder of her trip?

\textbf{(A)}\ 29\quad \textbf{(B)}\ 24\quad \textbf{(C)}\ 27\quad \textbf{(D)}\ 32\quad \textbf{(E)}\ 26

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Gauss contests here.