MathDB
2021 LMT Spring Division A Problem 14

Source:

October 22, 2021

Problem Statement

Alex, Bob, and Chris are driving cars down a road at distinct constant rates. All people are driving a positive integer number of miles per hour. All of their cars are 1515 feet long. It takes Alex 11 second longer to completely pass Chris than it takes Bob to completely pass Chris. The passing time is defined as the time where their cars overlap. Find the smallest possible sum of their speeds, in miles per hour.
Proposed by Sammy Charney