In this case for part A:

D = what must be found.

r = 22 m/s

t = 30 minutes * 60 seconds/minute = 1800 seconds. (Convert minutes to seconds because the speed is given in meters per second.)

D = 22*1800 = 39600 meters = 39.6 kilometers from town.

Part B: Use D=rt to find how far the train traveled in 50 seconds.

D = what must be found.

r = 22 m/s

t = 50 seconds.

D = 22 * 50 = 1100 meters.

The train began 300 meters south of town, which the problem specifies as -300. It moved 1100 meters north, which is +1100, so its position is now:

1100-300= 800. For the problem, +800 means 800 meters north of town.

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