This is a slightly challenging problem from BL’s Math Games.
“In a square garden ABCD of side 10m, a sheep sets off from B and moves along BC at 30cm per minute. At the same time, you set off from C and move along edge CD at 40cm per minute. The question is, what’s the shortest distance between you and the sheep in meters?
This is somewhat an optimization problem because as you and the sheep move along the sides of the square at different rates, the distance in between varies as you can imagine.”
There’s at least one non-calculus solution and of course one calculus solution.
See Sheep in Garden Problem for solutions.