Maggie is a good inventor. If she invents one invention this year, when she is 7, and two inventions when she is 8, and three inventions when she is 9, etc. , how many inventions will she make when she is 25?

Bonus: Maggie's grandfather started inventing when he was 7, too. He also invented two inventions when he was 8, etc. He just turned 70. How many inventions will he make this year?