Merge pull request #46 from Dick-Lane/master

Change conjunction "and" into article "an".
Merge pull request #47 from Dick-Lane/master

Clarify description and task.
correct one answer; add solution text.
make displayed answer reflect solution; add solution
clean up display of percent signs.
correct typo.
correct typo.
make minor wording change.
improve formatting, add solution.
add solution.
catch special cases in random value generation, add solution.
add solution.
add solution.
correct typo.
add solution.
correct typos, add solution.  added commented out second part.
make very slight improvement to problem formatting.
improve parameter selection.
improve problem wording, use MathObjects.
increase numerical tolerance to allow use of a table to estimate probabilities.