SAT Mathematics Practice Test 4

In Amelia’s training schedule, her longest run in week 16 will be 26 miles and her longest run in week 4 will be 8 miles. Thus, Amelia increases the distance of her longest run by 18 miles over the course of 12 weeks. Since Amelia increases the distance of her longest run each week by a constant amount, the amount she increases the distance of her longest run each week is $\frac{26-8}{16}-4=\frac{18}{12}=\frac{3}{2}=1.5$ miles
Choices A, B, and C are incorrect because none of these training scheduleswould result in increasing Amelia’s longest run from 8 miles in week 4 to 26 miles in week 16. For example, choice A is incorrect because if Amelia increases the distance of her longest run by 0.5 miles each week and has her longest run of 8 miles in week 4, her longest run in week 16 would be $8+0.5\bullet 12=14$ miles, not 26 miles.