The rider covered 5 km in the first 40 minutes. The next hour he moved at a speed of 10 km / h, and the remaining 6 km

| September 2, 2021 | education

The rider covered 5 km in the first 40 minutes. The next hour he moved at a speed of 10 km / h, and the remaining 6 km of the way – at a speed of 12 km / h. Determine the rider’s average speed over the entire movement.

Initial data: the first section of the path (t1 = 40 min (2/3 h), S1 = 5 km); the second section of the path (t2 = 1 h; V2 = 10 km / h); the third section of the route (S3 = 6 km; V3 = 12 km / h).

The average speed of the rider for the entire time of movement is determined by the formula: Vav. = S / t = (S1 + S2 + S3) / (t1 + t2 + t3) = (S1 + V2 * t2 + S3) / (t1 + t2 + S3 / V3).

Calculation: Vav. = (5 + 10 * 1 + 6) / (2/3 + 1 + 6/12) = 21/13/6 = 21 * 6/13 = 9.69 km / h.

Answer: The rider’s average speed for the entire movement is 9.69 km / h.



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