cant work this out myself.

[Dave7]

"A bit more than 6mph" is a better answer than "6.3157894 mph". Partly because it's more useful, partly because the latter answer implies that you can measure both time and distance accurately to the 8th decimal place - that is to the nearest micron and microsecond respectively.

It implies that my Casio £2.99 calculator gave me those 7 decimal places

 

[ushills]

"A bit more than 6mph" is a better answer than "6.3157894 mph". Partly because it's more useful, partly because the latter answer implies that you can measure both time and distance accurately to the 8th decimal place - that is to the nearest micron and microsecond respectively.

When doing my engineering degree we were told how many significant digits to use based on the information we started with, buggered if I can remember it now though.

Any ideas?

I would suggest that 2mph in 19 minutes should be rounded to 6.32mph on the basis that 1 minute is 0.02 of an hour, however, i'm not sure if that's how it works.

 

[srw]

I'd suggest that 2 miles (give or take) in 19 minutes (give or take) is a bit more than 6mph - and there's no more accurate answer that is reasonable to give. Unless the OP's gone out with a tape measure and used a stopwatch, in which case 6.3mph might be a reasonable answer.

 

[ushills]

http://www.physics.uoguelph.ca/tutorials/sig_fig/SIG_dig.htm

For those that have the time.

 

[Big boy]

Maths was never my best subject, times tables etc no problem.
I do struggle to work things out like that though. i do apresiate the effort people ty

 

[Norm]

I'd suggest that 2 miles (give or take) in 19 minutes (give or take) is a bit more than 6mph - and there's no more accurate answer that is reasonable to give. Unless the OP's gone out with a tape measure and used a stopwatch, in which case 6.3mph might be a reasonable answer.

This.

Given that '2 miles' is most likely somewhere between 1.6 and 2, and 19 minutes is anything up to 19 mins and 59 seconds, I reckon any answer more detailed than 'About 6mph' assumes a level of accuracy that cannot be justified.

 

[Big boy]

right
As its been said everyone has ad a bite on this one...
Me and the other half are pretty matey with the couple next door, we know he kick boxes regulary.
We often se him after his run puffin and pantin, we know where he runs to and asked how long it takes him.
The other day we got chattin and i said go on mate i will time you.
That is where all this came from, neither of us could work it out.
i used to run a forum some years ago, 95% of the members were great.
The other lot were just there with sarcastic comments, and just did their best to play devils advocate.
People grow a very long neck behind a keyboard, imagine this....
Im in a que trying to work out if i have the right change, would it be ok for someone to say to me did they not teach maths in your school??
No as if they did theywould know the possible result, then why do it on here???
As i said before thank you to all that helped worked this one out for me.