The cyclist traveled 36 km at a speed of 24 km / h before his bike broke. He repaired it for an hour
| May 11, 2021 | education
The cyclist traveled 36 km at a speed of 24 km / h before his bike broke. He repaired it for an hour, then turned home and walked 10 km at a speed of 5 km / h. Then he stopped a passing car and drove home in half an hour. Find the average speed of the cyclist’s path.
Given: cycling S1 = 36 km, V1 = 24 km / h; bike repair S2 = 0, V2 = 0, t2 = 1 h; walking S3 = 10 km, V3 = 5 km / h; driving a passing car S4 = S1 – S3, t4 = 30 minutes = 0.5 hours.
The average speed of a cyclist is determined by the formula: Vav = S / t = (S1 + S2 + S3 + S4) / (t1 + t2 + t3 + t4) = (S1 + S2 + S3 + S1 – S3) / (S1 / V1 + t2 + S3 / V3 + t4) = (2S1 + S2) / (S1 / V1 + t2 + S3 / V3 + t4).
Calculation: Vav = (2 * 36 + 0) / (36/24 + 1 + 10/5 + 0.5) = 72/5 = 14.4 km / h.
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