Respuesta :

The answer is C. 30%
   1,680
÷ 400
= 4.2   Xian has completed 4.2 LAPS of the track,

  400
x  14
= 5,600  So this is the total amount of yards in the track

  5,600
- 1,680
=3,920 So this is how many yards are left for Xian to run

  3,920
÷   400
= 9.8  This is how many laps Xian has to run

4.2 + 9.8 = 14

so estimating how many laps Xian has run compared to how many he has left, he has completed 30% of the track.