The man covered the first half of the journey at a speed of 5 km / h. Determine the speed on the second section
| February 13, 2021 | education
The man covered the first half of the journey at a speed of 5 km / h. Determine the speed on the second section of the route if the average speed is 3 km / h.
To find the value of the speed of the specified person on the second section of the path, we apply the formula (we take into account that S1 = S2 = S / 2): Vav = S / (S1 / V1 + S2 / V2) = 1 / (1 / 2V1 + 1 / 2V2).
Values of the variables: V1 – initial ground speed (V1 = 5 km / h); Vav – average speed (Vav = 3 km / h).
Calculation: 3 = 1 / (1 / 2V1 + 1 / (2 * 5)).
1/3 = 1 / 2V1 + 1/10.
1 / 2V1 = 1/3 – 1/10 = 7/30.
2V1 = 30/7.
V1 = 30/14 = 2.14 km / h.
Answer: On the second section of the route, the specified person had a speed of 2.14 km / h.
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