If you travel a distance of $350\mathrm{km}$ in a time of $5.15h$, what must be your average speed?

• A. $350+5.15\mathrm{km}/h$ (approximately $355.15\mathrm{km}/h$)
• B. $\frac{5.15}{350}\mathrm{km}/h$ (approximately $0.0147\mathrm{km}/h$)
• C. $350-5.15\mathrm{km}/h$ (approximately $344.85\mathrm{km}/h$)
• D. $\frac{350}{5.15}\mathrm{km}/h$ (approximately $68.0\mathrm{km}/h$)

Answer: (D)

Verified step by step guidance

1. Identify the given quantities: the distance traveled \(d = 350\ \text{km}\) and the time taken \(t = 5.15\ \text{h}\).
2. Recall the formula for average speed, which is the total distance divided by the total time: \(v_{avg} = \frac{d}{t}\).
3. Substitute the given values into the formula: \(v_{avg} = \frac{350}{5.15}\) km/h.
4. Perform the division to find the average speed (do not calculate the final number here, just set up the expression).
5. Interpret the result as the average speed in kilometers per hour, which tells you how fast you must travel on average to cover 350 km in 5.15 hours.