The test as originally transcribed did not say ‘$20 per meter’ but “$20 per m’:
http://skyways.lib.ks.us/genweb/saline/society/exam.html
I suspect that ‘m’ did not mean meters but a thousand board feet (as used on this page: http://ezinearticles.com/?id=1886359 )
In which case (assuming 1-inch boards) the answer would be 40 * 16 * $20 / 1000 = $12.80. Comments?
Oops, meant to ping everyone that was discussing meters...
$20 would have been fantastically expensive per meter in 1895, so there is definately good reason to think that it is perhaps not referencing meters.
Ah ha. Now that would make sense. I think you just aced that question.
That would be a perfectly practical question for that era.
I suspect that m did not mean meters but a thousand board feet (as used on this page: http://ezinearticles.com/?id=1886359 )
You are correct. That is what it means.