A car travels for .50 of a trip at 20 km/h. How fast must it travel in the second half to average 55 kmh?
To find out how fast the car must travel in the second half to average 55 km/h, we can use the concept of average speed. Average speed is calculated by dividing the total distance traveled by the total time taken.
Let's denote the total distance traveled by the car as D. Since the car travels for only half of the trip at 20 km/h, the distance traveled in the first half would be (0.5 * D). Therefore, the distance traveled in the second half would also be (0.5 * D).
Now, let's consider the time taken for each half of the trip. The time taken for the first half of the trip can be calculated by dividing the distance traveled in the first half (0.5 * D) by the speed of 20 km/h. Hence, the time taken for the first half would be ((0.5 * D) / 20).
To calculate the average speed of the entire trip, we need to sum up the distances and divide by the total time taken. Since the distance traveled in the second half is also (0.5 * D), the total distance would be (0.5 * D) + (0.5 * D) = D.
The time taken for the second half of the trip can be calculated by dividing the distance traveled in the second half (0.5 * D) by the speed of the second half (let's denote it as v). Hence, the time taken for the second half would be ((0.5 * D) / v).
To calculate the average speed of the entire trip, we can use the formula: Average Speed = Total Distance / Total Time.
Therefore, we have the equation: 55 = D / (((0.5 * D) / 20) + ((0.5 * D) / v)).
Now, we can solve this equation for v, which represents the speed the car needs to travel in the second half to average 55 km/h.
pick a convenient distance and try to calculate
220 is divisible by 20 and 55