FERMAT 2007 Problem 8

Ivan trained for a cross-country meet.
On Monday, he ran a certain distance.
On Tuesday, he ran twice as far as he ran on Monday.
On Wednesday, he ran half as far as he ran on Tuesday.
On Thursday, he ran half as far as he ran on Wednesday.
On Friday, he ran twice as far as he ran on Thursday.

If the shortest distance that he ran on any of the five days is 5\:km, how far did he run in total?

Answer Choices
A. 55\:km
B. 25\:km
C. 27.5\:km
D. 17.5\:km
E. 50\:km