Please help me with the following problem:
Joe is on a cross-country trip from New York to Los Angeles. He drives for 45.0 min at 70.0 km/h, 10.0 min at 95 km/h, and 30.0 min at 55.0 km/h, and he spends 20.0 min eating lunch and buying gas. What is the average speed for this part of his trip?
a. 67.6 km/h
b. 68.4 km/h - I did b as a guess, because I couldn't figure the answer, but I got it wrong
c. 54.7 km/h
d. 53.8 km/h
Two things that I did to help me were:
Delta d
--------
Delta t
and
m - m
-------
s - s
distance is m - m is meters
time is s - seconds
For the second one I did kilometer over hour.
I have no idea on how to do this, and I have no idea of if I am doing it right or not. I have tried distance over time tons of times, and I get different answers than the ones above. Can you guys help me please? I will greatly appreciate it.
Below is what bobpursley did to try to help me. I have not tried his way, and I do not know how to do his way. With his way, the lesson did not teach me how to do this.
bobpursley said this:
"average velocity=distance/time
distance=3/4*70+1/6*95 + 1/2*55
time= (45+10+30)/60
check my thinking. I get none of the answers. "
I am confused too, because he turn the minuted into seconds, but in fraction form. My home-school lesson did not teach me that. Please help me, I have been stuck on this problem for a couple days!
a. D = d1 + d2 + d3 =
70*(45/60) + 95*(10/60) + 55*(30/60) =
95.83 km.
T = 45 + 10 + 30 + 20=105 min=1.75 h.
Avg. Speed=D/T=95.83km/1.75h=54.8 km/h.
NOTE: My procedure is the same as Bob's,
but he forgot to include the 20 min for
eating and buying gas. Your answer in
Part a does not include the 20 min either.
Thank you Henry! :)
This exact queston is on my edenuity...thank you
To solve this problem, we need to find the total distance traveled and the total time taken, and then divide the distance by the time to get the average speed.
First, let's calculate the distance traveled at each speed:
The distance traveled at 70.0 km/h for 45.0 min (0.75 hours) is:
Distance1 = speed1 × time1 = 70.0 km/h × 0.75 hours = 52.5 km
The distance traveled at 95 km/h for 10.0 min (0.17 hours) is:
Distance2 = speed2 × time2 = 95 km/h × 0.17 hours = 16.15 km
The distance traveled at 55.0 km/h for 30.0 min (0.5 hours) is:
Distance3 = speed3 × time3 = 55.0 km/h × 0.5 hours = 27.5 km
Next, let's calculate the total distance:
Total distance = Distance1 + Distance2 + Distance3 = 52.5 km + 16.15 km + 27.5 km = 96.15 km
Now, let's calculate the total time taken:
Total time = time1 + time2 + time3 + time for lunch and gas = 45.0 min + 10.0 min + 30.0 min + 20.0 min = 105.0 min = 1.75 hours
Finally, let's calculate the average speed by dividing the total distance by the total time:
Average speed = Total distance / Total time = 96.15 km / 1.75 hours = 54.91 km/h
Rounding to the nearest tenth, the average speed for this part of the trip is 54.9 km/h.
None of the provided answer choices match exactly with our calculated average speed of 54.9 km/h, so it seems like the correct answer might not be among the options given. You could choose the closest option, which in this case would be c. 54.7 km/h, but it is important to note that none of the options are an exact match for the actual average speed calculated.