1. The heaviest letter you can mail to Mexico is one that weighs 3.5 ounces because in the set of rules we can observe that this is the biggest value for the independent variable w.
2. If we mail a letter that weighed 2 ounces, we would have to pay 1.72 dollars, we know that because the second rule is for a letter that weighs more than 1 ounce to less or equal (because of the symbol ≤) 2 ounces. Then if the letter weighs 2 ounces, we have to apply the second rule, which sets a payment of 1.72 dollars.
