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Topic: Marilyn snubs Algebra I, again
Replies: 3   Last Post: Nov 27, 2000 11:16 AM

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Domenico Rosa

Posts: 455
Registered: 12/4/04
Marilyn snubs Algebra I, again
Posted: Nov 20, 2000 9:46 PM
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On 1 October 2000, Marilyn vos Savant's column contained the following
problem sent by Joe Black of Athens, TX. "Say that two motorboats on
opposite shores of a river start moving toward each other, but at
different speeds. (Neglect all other factors, like acceleration,
turn-around and current.) When they pass each other the first time, they
are 700 yards from one shoreline. They continue to the opposite shore,
then turn around and start moving toward each other again. When they
pass the second time, they are 300 yards from the other shoreline.
(Their speeds, although different, remain constant.) How wide is the

On 19 November 2000, Marilyn published the following letter from Peter
Mantos of Albuquerque, NM. "I found it interesting that the recent
motorboat/river problem is _not_ solvable in a straightforward
mathematical way: The problem appears to have five unknowns and only
four equations. But you demonstrated that it can be solved with pure

Marilyn says that she has "heard from 462(!) readers, including plenty
of mathematicians and other professionals, who fervently believe my
answer is wrong."

Although there is overwhelming evidence that many professionals are
completely stumped by Algebra I problems, I am surprised that any
mathematician would question her answer.

When I first read the problem, I worked on it without reading her
solution. I made the same observations 1), 2) and 3) that Marilyn made,
but I did not reach her observations 4) and 5). Based on the way I was
taught by Miss Phoebe Fitzpatrick, I identified one unknown and tried to
derive an equation. The first equation reduced to an identity. The
second yielded a quadratic equation with the same solution that Marilyn
obtained logically.

The second letter is indicative of the twisted way in which Algebra I
continues to be taught. It gives readers the fallacious impression that
this "problem is _not_ solvable in a straightforward mathematical way:
The problem appears to have five unknowns and only four equations." Why
does Marilyn continue to promote this type of nonsense?

Dom Rosa

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