Official Solution: Two cyclists, Alex and Jordan, are cycling around a circular track. If they start at exactly the same time, in how many seconds will Alex have completed exactly one more lap than Jordan? (1) Alex completes each lap in 20 seconds and Jordan completes each lap in 25 seconds.
In every 25 seconds, Jordan completes 1 lap, while Alex completes 1.25 laps (1 lap plus 25% of the lap). So Alex gains 0.25 laps on Jordan every 25 seconds. To gain 1 full lap, Alex needs 4 such intervals: 25 * 4 = 100 seconds. Sufficient.
(2) They start at the same point on the track and cycle in the same direction.
This information is irrelevant. The starting point and direction do not affect the time it takes for one cyclist to complete exactly one more lap than the other. Not sufficient.
Answer: A