Running maths question?

Question

If i run at 4.5mins/km and my friend runs at 5mins/km then how far will I have to run until I am 1km ahead of my friend

Answer 1

45 minutes,  oops sorry, 10 km.

Answer 2

10 km or 45 minutes

Answer 3

another two and a half mins

Answer 4

You can't be ahead of your friend, unless they stop.

Answer 5

2 minutes

Answer 6

It is  10 Km

- - -

For every 5 minutes the two of you run, you are .1 Km ahead of her/him.  

5 is to 1Km as .5 is to xKm = .1Km

So now we ask how many times must this ratio occur before .1Km turns into 1Km

.1x = 1

x = 1/.1 = 10.0

- - -

To check this:

10 times 5 = 50 minutes (friend's time to run same distance)

10 times 4.5 = 45 minutes (you)

50min - 5min = 45min (the time in which you ran 10 Km)

45min/5Km per min (friend's rate) = 9 Km

Therefore:

in 45 minutes your friend will have run 9 Km, but you will have run 10 Km.

Answer 7

that dosn't make sense

anyway i'm only 10 so i can't exactly do it

Answer 8

Never, cos ur running slower! (or 80,157.14 km until hes run round the world and caught up again)

Answer 9

you can cover 10 k in 45 mins

he can only cover 9 k in same time