Posted on 10/13/2012 2:57:36 PM PDT by James C. Bennett
It’s a trick question. There is no speed you can travel the second mile and end up with a 30mph average over the two mile course. It’s impossible since you took 4 minutes to do the first mile.
You must travel the entire two miles in exactly four minutes to average 30mph.
Instant acceleration is not needed as it was stated as the max average speed the car could do for one mile up the hill.
This means it attained a speed faster than 15mph at some point on the uphill leg.
Time is not the issue.
Answer this riddle:
If you go 15mph for 1 mile and 45mph for 1 mile, what is your average SPEED in MPH for the two mile trip ?
Oh My! I feel your pain FRiend, I'm also up there with you. It's a shame our IQ does not match our tonnage :-)
She edged me out by 100.
But the question is about speed, and not time. Time is not in any of the givens. Time is a factor in determining MPH, but so is DISTANCE.
The issue is how you get AVERAGE MPH, not AVERAGE TIME.
Look at it this way:
IF I go 15mph for 1 mile, and 45mph for 1 mile, what is my average speed (mph) for a 2 mile course?
Doesn’t matter how darn long it took
If that’s true then it gets more complicated than the simple 15/45 answer. Once at the top of the hill how much time will it take to accelerate from 15mph to 45mph. That is an unknown factor and next to impossible to figure the mph necessary to offset this acceleration time to finally reach the 30mph average.
Einstein, himself, said there was no time left.
No one should feel dumb because they did not get the proper answer to this question at once. After all, Einstein was stumped for a short time by this same question.
Once you see the trick, you will never be fooled by a similar question again. Indeed, if you took an IQ test and kept this question and how the trick was played in mind you would score higher than you would have had you never seen this question.
Just as in the real world, you MUST distill a problem down to its fundamentals. This is what a genius like Einstein did.
I can tell you that the unforgiving world of real-time programming will soon teach you how to get down to the bare facts.
If I’m in a top fuel dragster,
and I do 100mph for one mile, and then I go 300mph for the second mile, what is the average MPH for a 2 mile trip ?
“Attended one and only one Mensa meeting.”
As mentioned earlier, I was stunned by what complete jerks most of them were. There was no way I wanted any of them as friends. I was expecting much more, and was profoundly disappointed. So,,, I kept on making poor decisions on my own! I really wish I had never gotten involved in music, but it catered to my creative side, when my schooling was just failing to provide me with what I really craved! I’m a very good guitarist,,,, but I haven’t touched a guitar in two years, except to move it out of my way. Very sad.
Nope. Average speed is total distance divided by total time. 2 miles/5.2 minutes = 23.077 miles per hour.
Doesn’t matter how darn long it took.
I think it does matter. To average 30mph the trip will take 4 minutes. You can go 100mph part of the trip and 10 mph some of it and 33mph some of it or 80mph some of it but the given is that you must average 30mph the whole trip. That is 4 minutes maximum allowed to make that 30mph average. You’ve used up 4 minutes going the first mile. No time left unless you can make it to the bottom of the hill instantaneously.
no “return trip” mentioned.
Sorry, my error. I didn’t mean return trip.
Which has absolutely nothing to do with average MPH.
Let's say that during the first mile, you went 5, then 10, then 15 mph, at each third of a mile. What would your average MPH for the mile course be? How long would it take? And what does it matter ? The answer you are working on is AVE MPH, not TIME.
If you are GIVEN MPH and DISTANCE, the outcome is 'time'. Therefore it cannot be the INPUT factor.
I knew four mensa people — one who became a warehouse manager, one who became a paralegal and never bothered to finish college, one who was the secretary of the president of the company (who couldn’t beat her on the test), and one who became a mid-level manager in a human resources department.
100 mph for 1 mile, 36 seconds. (0.01 hours)
300 mph for 1 mile, 12 seconds. (0.00333333 hours)
Total distance traveled, 2 miles.
Total time, 0.01333333 hours. (48 seconds)
Average speed, 150 MPH.
Interesting about your career in music versus your high aptitude in architecture. I can relate somewhat (not the ultra-high IQ part) in that I have strong aptitudes in music and in math/physics. I chose a career in engineering, and this has worked out very well for me, but I have always felt like I have failed to find a way to adequately express my musical ability - I am considering doing something about this, with tentative plans to create a blog to share my compositions and arrangements. I actually majored in music one year...surprisingly, engineering was much easier for me.
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