Engineering sense of the correct answer in the calculations

"The street car will break with 230 men?"

I guess it is to prevent the standing passengers from getting crushed, if you let more than 229 in....

I wonder what the personal space per person is that they calculated with.

In general, the (numeric) answer to a problem should not have more significant digits than the smallest number of siginificant digits of the input data.

If that is that what your '-1' setting is doing in Mathcad Prime Minister, then it should not be a '-1' setting on decimals, but rather a check box, that applies to most of the formats.

Success with the implementation.

Luc