2023 AMC 10A Problem 1

Below is the professionally curated solution for Problem 1 of the 2023 AMC 10A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2023 AMC 10A solutions, or check the answer key.

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Concepts:relative speeddistance rate and time

Difficulty rating: 890

1.

Cities AA and BB are 4545 miles apart. Alice and Beth start biking from AA and BB at speeds of 1818 mph and 1212 mph, respectively. How far away from city AA will they be when they meet?

2020

2424

2525

2626

2727

Solution:

They ride toward each other, so their speeds add. That closes the 4545-mile gap at 18+12=3018 + 12 = 30 mph, and they meet after 45/30=1.545/30 = 1.5 hours. Alice starts at A,A, so by then she's gone 181.5=2718 \cdot 1.5 = 27 miles. Thus, E is the correct answer.

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