The Ship's Ladder Problem .................................................

Mildred^* was struggling over her math homework. Her father wouldn't help her, still feeling the sting of being out-negotiated and having to pay her a $300 monthly allowance.

^*Not her real name

Here's the problem that was stumping her:
"A ladder hangs over the side of a ship anchored in port. The bottom rung touches the water. The distance between rungs is 20 cm and the total length of the ladder is 180 cm. The tide is rising at a rate of 15 cm per hour. When will the water reach the sixth rung from the top?"
Notebook pages with her calculations were scattered all over the floor. The dog was trying to be helpful by eating them.

The problem does in fact resemble a typical math 7 word problem, and Mildred would eventually have come up with the quite reasonable answer of 4 hours, and if her teacher hadn't been such a prankster, she would have gotten it right.

Fortunately her retired math teacher grandfather was in the room, although not wearing his cape, and he was able to provide the one true answer. What was it?

Check your answer by holding the mouse cursor over the alligator below

The boat is floating. The ladder will rise
with the boat as the tide comes in. So the
water level will remain at the bottom rung.

The boat is floating. The ladder will rise
with the boat as the tide comes in. So the
water level will remain at the bottom rung.

Meanwhile, we have a page about alligators and crocodiles! We have pages about everything!

Math Teacher Tales

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