The Restless Fly
Two cyclists began a training run simultaneously.
One starting from Sofia(Bulgaria), the other from Yambol(Bulgaria).
When the riders were 180 miles apart, a fly took an interest. Starting on the cyclist's shoulder, the fly flew ahead to meet the other cyclist. On reaching the latter, the fly at once turned back.
The restless fly continued to shuttle back and forth until the pair met.
The fly's speed was 30 miles per hour. Each cyclist's speed was 15 miles per hour.
How many miles did the fly travel?