Random problems for fun?

[paralinx]

I'm bored so I want to post some random physics or math problems to see how smart you guys are.

Won't this be fun? haha ok I'll only post one problem until it's solved, and if no one responds i'll just delete the thread or something.

Problem #1 (Physics) we'll start with an easy one:

What is the average speed of a car that travels 230 miles in 3.25 hours?

[DomoCobra]

Distance/Time=Speed 230Miles/3.25Hours = 70.8 Miles per hour (just over the UK speed limit)

[eranga262154]

Distance/Time=Speed 230Miles/3.25Hours = 70.8 Miles per hour (just over the UK speed limit)

I agreed with this if it is a real one. But I'm not sure what are you going to do here. Let see.

[Rassis]

That is too easy. Try this one:

You move from a town to another one which is 300 Km away. You drive the first half of the way at a speed of 100 Km/hour and the second half at 150 Km/hour. What was the average speed?

[Mattywoo2]

"You drive the first half of the way at a speed of 100 Km/hour"

First let's see how long it took to get there:

150km/(100km/hour) = 1.5 hours
150km/(150km/hour) = 1 hour

Total journey time = 2.5 hours

Now calculate average speed:

300km/2.5hours = 120km/hour

[Rassis]

The answer is, of course, correct. This question uses to be a little bit tricky when asked "in cold blood" because people tend to answer 125 Km/hour, or the arithmetic mean instead of the harmonic mean (120 Km/hour) as it should be. Try with a friend...

[eranga262154]

The answer is, of course, correct. This question uses to be a little bit tricky when asked "in cold blood" because people tend to answer 125 Km/hour, or the arithmetic mean instead of the harmonic mean (120 Km/hour) as it should be. Try with a friend...

Ya, it's true. I think most of the people will get that 1256Km/hour, because they tebd to feel with average value.