Puzzle #26: Grandma’s Killer Pie

Until the new winter semester gets started in January, I will be rerunning past puzzles.

Grandma makes apple pie that is simply to die for.

If the fatal dose is one-quarter of a pie per 100 lbs. of body weight, will two pies be sufficient to off the rest of the family?

The rest of the family consists of Peter (200 lbs.); Susan (120 lbs.); their three children, Joseph (60 lbs.), Samantha (40 lbs.), and James (40 lbs.); Roberta (140 lbs.); and Tom (170 lbs.).

Scenarios:

1. Grandma has a nifty pie-cutter that cuts pie into twelve equal pieces. Each person gets a whole number of pieces. Assume clean cuts with no pie adhering to the pie-cutter.
2. As in #1, but the pie-cutter cuts pie into ten equal pieces.
3. As in #2, but Tom recently ran a marathon and lost ten pounds.

Submit your answer to Gene Wirchenko <genew@telus.net>. Your answer should be in the form of a proof. That means to show how your answer must be correct. The deadline is Wednesday, December 4, 2013 at noon Pacific Time. I will post the answer shortly after.