Can someone do the math for me so I can make sure I'm doing it right?

So I'm going on a trip soon and the trip takes 3:59 hours to get to my destination...so 4 hours. I have an 07 Saturn Ion and it gets 21 city MPG and 30 highway MPG. It's gas tank can hold 13 gallons of gas. The trip said from my location to the end destination would take 197 miles...so 200 miles. If I filled up my gas tank to all the way full, 21*13=273....so essentially I would be able to travel 273 miles before I would have to fill up again if I was going let's say 45 MPH the entire way? So basically I would have to only get gas one time to get to my destination correct? Sorry, I'm trying to figure out the amount of money I need to budget for gas lol

PreCalc II ---Circles Question?

A small radio transmitter broadcasts in a 42 mile radius. If you drive along a straight line from a city 55 miles north of the transmitter to a second city 54 miles east of the transmitter, during how much of the drive will you pick up a signal from the transmitter?

Iraqi PM: ISIS plot to attack US, Paris subways

http://news.msn.com/world/iraqi-pm-plot-...

The people who use transit daily know, its still a free for all down there. No metal detectors or anything, maybe like 1 bomb sniffing K-9 scouting an area for like an hour max. Its not really a "controlled" environment these subways you know. Kind of paranoid, what say you? Just relax?

Help with MBTA zones!?

I have a monthly pass for Zone 1A however I am not sure where I can travel with that. Does it only work on the subway? I need a pass for the red line and then for the bus in Belmont but I am not sure if the zone 1A pass can be used on local busses