2017 AMC 8 Problem 23

Attempt Problem 23 of the 2017 AMC 8 below, then check your answer against the video solution and professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2017 AMC 8 solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

23.

Each day for four days, Linda traveled for one hour at a speed that resulted in her traveling one mile in an integer number of minutes. Each day after the first, her speed decreased so that the number of minutes to travel one mile increased by 55 minutes over the preceding day. Each of the four days, her distance traveled was also an integer number of miles. What was the total number of miles for the four trips?
10 10
15 15
25 25
50 50
82 82
Answer: C
Concepts:factorarithmetic sequence
Small hint:
Each day’s minutes per mile must divide 6060.
Big hint:
List the divisors of 6060 and find four of them spaced 55 apart.
Video solution:
Solution video thumbnail
Play video

Click to load, then click again to play

Written solution:
Linda traveled for 6060 minutes every day. Since one mile was traveled in an integer amount of minutes each day, her minutes per mile every day must be a factor of 60.60. The factors of 6060 are 1,1, 2,2, 3,3, 4,4, 5,5, 6,6, 10,10, 12,12, 15,15, 20,20, 30,30, and 60.60. The only sequence of four of these numbers that differ by 55 are 5,5, 10,10, 15,15, and 20.20. For the four days, she traveled 605+6010+6015+6020=25 \dfrac{60}{5} + \dfrac{60}{10} + \dfrac{60}{15} + \dfrac{60}{20} = 25 miles in total.
Thus, C is the correct answer.
LIVE by Po-Shen Loh
Programs

LIVE Classes

Self-Paced Classes

Stars

Scholarship

About Us

Who Is Po-Shen Loh?

Email Contact

Newsletter

Jobs

Become a Star

For a more Thought Full world.

© 2026 Expii, Inc.