My initial thought on the answer to the trip problem was 60 mph, which as we discussed is what most people think the answer is at first. I thought that was the answer because the only thing I payed attention to in the problem was the average miles per hour instead of looking more into the per hour part. Because I only looked at the average, I added up the three speeds that would get the driver an average of 60 and figured "that was easy!" This was, obviously, not the correct answer. I learned that I need to read the problem carefully and figure out exactly what I am trying to find instead of basing everything off of my first impression.
The correct answer to the problem, which we found out later, is that the car needs to travel faster than the speed of light to go an average of 40 km/h in one hour. In order to solve this problem, you need to know the following. You need to know that the driver wants to travel 40 km/h in one hour. He has already driven 20 kilometers at an average of 40 km/h and then 10 kilometers for an average of 20 km/h. You also need to know that speed equals distance divided by time. If you rearrange that, you can get that time equals distance divided by speed. Therefore, for the 20 kilometers going 40 km/h equals .5, which is hours translates to half an hour. The 10 kilometers going 20km/h also translates to .5, which means the driver has already traveled an hour. Therefore, because he has already traveled an hour, he must immediately get to the end of the 40 kilometers, and the only way to do that is to travel at the speed of light.
What I learned about my problem solving skills is that I've been trained to skim over the problem and quickly solve it for what I think is the write answer. I will remember, after this experience, that I need to read the problem carefully and write things down in order to know how to get the correct answer.
1. I love how in detailed your response was on how to solve the problem correctly. The way you phrased your answer and carefully explained every part made me understand the problem even more.
ReplyDelete2. I too did not read the problem correctly, and tried to rush through. I also learned that this method doesnt create good results and that i should read the problem carefully and show all of my work.
3. I did not get 60 m/h for my first guess, i instead somewhat guessed what i thought would be most logical. At least you had a reasoning for your answer even if it wasnt the right reasoning.
4. I dont have much critism for your blog, as i thought it had very clear and thorough details. But remember to follow the advice you gave yourself and read the problem and remember all parts of it, and most importantly when solving it to write everything down.