Stat 100

[Alex]

One additional comment on part b. You ran into a very handy way of knowing when you've gone astray with probabilities.

When asked for the probability of something happening the answer can never be less than 0 (or 0%, or never) or greater than 1 (or 100%, or every time). So, since you received an answer of of something having a probably of 2.4 (or 240%) you can know you went astray.