Cory has 15 die-cast cars in his collection. each year his collection increases by 20%. roger has 40 cars in his collection. each year he collects 1 additional car.

part a: write functions to represent cory and roger's collections throughout the years. (4 points)

part b: how many cars does cory have after 6 years? how many does roger have after the same number of years? (2 points)

part c: after approximately how many years is the number of cars that cory and roger have the same? justify your answer mathematically. (4 points)