Bob won $800 at bingo last night. the first thing bob did was to take a cab to his mothers house. he gave the cab driver $20 and told him keep the change. bob gave his mother 1/3 of his remaining winnings and walked down the street to his aunts house. he gave 25% of his money he had left. lastly bob gave one sixth of what he had left to his best friend and kept the rest for himself. how much money did bob keep