1999 AMC 12 Problem 9
Attempt Problem 9 of the 1999 AMC 12 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1999 AMC 12 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
9.
Before Ashley started a three-hour drive, her car’s odometer reading was a palindrome. (A palindrome is a number that reads the same way from left to right as it does from right to left.) At her destination, the odometer reading was another palindrome. If Ashley never exceeded the speed limit of miles per hour, which of the following was her greatest possible average speed?
Answer: D
Small hint:
List the palindromes just above
Big hint:
The distance in hours cannot exceed miles
Solution:
The palindromes after are and In three hours Ashley can drive at most miles.
Reaching would require miles, which is too far. Reaching requires miles, giving average speed miles per hour.
Thus, the correct answer is D.
Problem 9 in other years
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