The population of a southern city follows the exponential law. Use this information to answer parts a and b. (a) If N is the population of the city and t is the time in years, express N as a function of t. N(1 ) = Npekt (Type an expression using t as the variable and in terms of e.) (b) If the population doubled in size over 19 months and the current population is 30,000, what will the population be years from now? The population will be approximately people. (Do not round until the final answer. Then round to the nearest whole number as needed.)