Tag Archives: BL puzzles

ZigZag in Rectangle

This is another problem from BL’s Math Games.

“What fraction of the rectangle is colored?  Assume that M and N are midpoints of the sides of the rectangle.”

That they are midpoints was not stated explicitly in the problem as given in front of the subscription wall, but from the comments it became evident this was the case.

Initially I actually assumed the line was positioned arbitrarily.  What would be the solution in that case?

Answer to BL problem.

See ZigZag in Rectangle for a solution.

ChatGPT Problem

This problem is from BL’s Math Games.

“What’s the area of the red triangle?”

BL decided to see what kind of solution ChatGPT would come up with.  After several tries and prompts it seemed to oblige.  I don’t know what BL’s prompts were, and in the statement of the problem outside the subscription wall he never explicitly says what the problem is, namely, to find the area of the red triangle.

There also seems to be some ambiguity about the constraints on the problem, that is, how much of the appearance of the diagram should the solver assume?

Answer.

See ChatGPT Problem for a solution.

Sheep in Garden Problem

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.

Answer.

See Sheep in Garden Problem for solutions.

Whose Bullet?

Here is a probability problem from BL’s Weekly Math Games.  Normally I am not a fan of such problems, but this one seemed fairly straight-forward for a change.

“I hit the target 75% of the time. You hit the target 25% of the time.  We aim at the same time, and only one bullet hits.  What’s the probability it came from me?

Now as for this puzzle, it would be tempting to think that I am 3 times as good at hitting the target, but I am not!”

Answer.

See Whose Bullet for a solution

Sphere and Plane Puzzle

This is another puzzle from BL’s Weekly Math Games.

“a + b + c = 2, and

a2 + b2 + c2 = 12

where a, b, and c are real numbers.  What is the difference between the maximum and minimum possible values of c?”

The original problem statement mentioned a fourth real number d, but I considered it a typo, since it was not involved in the problem.

Answer.

See Sphere and Plane Puzzle for a solution.