GRE General Test: QR-174812 GRE Quantitative Reasoning

In a survey, 100 travel agents each ranked Airlines A, B, and C in order of preference. Each of the 100 travel agents also rated the three airlines in five categories on a scale of 1 through 10, with 10 being the best rating.

The sum of the five average ratings was calculated for each of the three airlines. The airline with the least sum was ranked 1st by what fraction of the travel agents?