A bakery opens with a certain number of regular customers. After opening, the bakery gains an average of 5 new regular customers per month (net increase). A linear equation
y=ax+b
is used to model the total number of regular customers y at the end of month x (where a and bb are constants). It is known that the total number of regular customers at the end of the 6th month is exactly twice the number at the end of the 2nd month. What is the value of b?