Question 829270
In a race, bicycles M and N start from the same point at the same time, traveling at 18 kilometers per hour and 10 kilometers per hour, respectively.
 If bicycle N finishes the race 2 minutes behind bicycle M,
 what is the length of the race in kilometers?
:
let d = distance of the race
Write a time equation; time = dist/speed
Slow time - fast time = 2 min
{{{d/10}}} - {{{d/18}}} = {{{2/60}}}; (time is in hrs)
multiply by 180 to clear the denominators, results:
18d - 10d = 3(2)
8d = 6
d = {{{6/8}}} = {{{3/4}}} km is the length of the race
:
:
See if that works, find the actual time of each
.75/10 = .075 hrs
.75/18 = .042 hrs
-------------------
difference .033 hrs
.033 * 60 = 1.98 ~ 2 min