Speed/time/distance sample problems
1. If you are traveling a distance of 10 miles and need to get to your destination within 2 hours, how fast would you need to go?
2. If you have been sailing at 6 knots for the last 3 hours, how far have you gone?
3. If you are sailing at 7 knots and will cover 21 miles before you arrive at the next mark, how long will it be before you arrive at that mark?
1. You are trying to find your speed so use the formula for speed: S = D/T. The distance to be covered is 10 miles and the time it will take is 2 hours. So, S = 10/2 = 5 knots. A “knot” is a nautical mile per hour. Unless you are in the Great Lakes, all miles are nautical miles on the water.
2. You are trying to find distance, so use the formula: D = S x T. The speed is 6 knots and the time is 3 hours. D = 6 x 3 = 18 miles covered over the last 3 hours.
3. You are trying to find time here: T = D/S. The distance to be covered is 21 miles and your speed is 7 knots. T = 21/7 = 3 hours before you get to the next mark.