Based on past experience, it is assumed that the number of flaws per foot in rolls of grade 2 paper follows a Poisson distribution with an average of 1 flaw per 5 feet of paper. Showing the details of your calculations, what is the probability that in a:

1. Find the expected number of flaws in a 1-foot roll, a 12-foot roll and a 50-foot roll.
2. 1-foot roll there will be at least 2 flaws?
3. 12-foot roll there will be at least 1 flaw?
4. 50-foot roll there will be between 5 and 15 (inclusive) flaws? You may use Excel or the lookup tables for this question. Specify the approach you used.