Read the following SAT test question and then click on a button to select your answer.

The time it takes Erica to run one mile decreased consistently throughout her track season. She estimates that her time to run a one-minute mile decreased by about 15 seconds for every 2 weeks into the season. If Erika ran one mile in 500 seconds at the start of the season, and x weeks after the start of the season ran one mile in 425 seconds, which of the following equations best represents this context?

A.500-7.5x=425
B.500-15x=425
C.500+7.5x=425
D.500+15x=425

来源:可可英语 http://www.kekenet.com/sat/202002/604889.shtml