Can you please answer this? i dont understand

Closing a credit card usually _your debt ratio.a. increasesb. decreasesc. improvesd. has no effect on

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?