Chemistry question about kilometers and miles?

Question

A slow jogger runs a mile in 13 minutes. Calculate the speed in kilometers per hour.

ive already calculated into meters and minutes, but this one is kiling me.

can you tell me how to do it, so i can learn too? thanks!

there are .6215 km in one mile.

Answer 1

(1 mi/13 min) x (.6215 km/1 mi) x (60 min/1 hr) = .6215 x 60 / 13 km/hr = 2.9 km/hr.  (Except it doesn't!)

Only problem is there is .6215 mi/1 km*, not .6215 km/1 mi!  So the answer is (1/13) x (1/.6215) x 60/1) = 7.4 km/hr!  (How is this a chemistry question, other than that it teaches you to convert units like you have to do in chemistry?)

* How do I know this?  (1 mi/1760 yd) x (1 yd/36 in) x (39.37 in/1 m) x (1000 m/1 km) = .6213 mi/1 km (approx.)

Answer 2

this is not a chemistry question anyway.lol.

since u know 1 mile = 0.6215 ,

and the jogger takes 13 minutes to complete a mile.

so, that means he takes 13/60 hours to complete 0.6215km,

therefore,

speed in kilometers per hour =

0.6215/(13/60)

where:

0.6215 in kilometer

13/60 in hour

the answer would be 2.86 something.

Answer 3

1 mile=0.6215km

1min=1/60  th of an hour

1mile/13min  =0.6215/[13x1/60]

                   =[0.6215x60]/13

                   =37.29/13

                   =2.8684615 km/hr