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Math Puzzle for September 19, 2025

Tristan races on despite obstacles, cheered by fans and family

Alameda Post - a boy walks barefoot through the grass [1]
Photo by Jeff Smith.

Tristan has trained assiduously for his first 10K race. Jolie, his mother, times him, standing at the 2-kilometer mark at 6 minutes. He starts off fast but a blowout on his left track shoe inhibits him; he presses on. Trevor, his father, times him from the 5-kilometer mark at 13 minutes.

A second blowout, this time on his right track shoe slows him a bit more. Layla, his sister, times him at the 8-kilometer mark at 28 minutes. Slugging through deep mud on the track slows him more, he remains undaunted.

Given his gradually diminishing speed, find his expected 10K finishing time.
(Hint: Tristan’s speed follows an exponential deceleration.)

Correct answers sent to [email protected] [2] could win a Tucker’s gift card.

Last week’s winner [3] was Matt Bliven with V = 27,000 cubic inches.

Jeff Smith is a former Math teacher and a retired US Navy Lieutenant Commander. Reach him at [email protected] [2].