How fast were the girls going

Question

Silvia rode her bike 40km in the same time as Tracy rode28km. Tracys rate was 3kmh slower how fast were they

Answer 1

Distance (d) equals velocity (v) times time (t).  Therefore, t=d/v.

 

Since they both rode for the same amount of time:  d1/v1 = d2/v2

 

40km/v1 = 28km/v2

 

Also, v2=v1 - 3 (since Tracy's rate was 3 km/h slower than Silvia's rate)

 

Substitution:

 

40km/v1 = 28km/(v1 - 3)

 

Cross-multiply:

 

40v1 - 120 = 28v1

 

12v1 = 120

 

v1 = 10

 

v2 = v1 - 3 = 10 - 3 = 7