1. Cell Phone Plans. You are comparing phone plans to determine which cell phone service you wish to go with. Verizon has a plan that is $11.95 per month, with 200 minutes of airtime, and $0.05 per minute after 200 minutes. T-Mobile has a plan that has $4.95 per month base fee, 450 minutes of airtime, and $0.08 per minute after 450 minutes. What is the critical airtime minute value where these plans collide: where the plans switch the "best value" distinction.