Rihanna has 5 less than 2 times as many homework problems to complete as her friend Terrika. The total number of homework problems that Rihanna and Terrika have left to complete is 19. Write a system of linear equations to model this situation and calculate the number of homework problems each girl has left to complete. Use r to represent the number of problems Rihanna must complete and t to represent the number of problems Terrika must complete.