2019 AMC 8 Problem 16
Attempt Problem 16 of the 2019 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 2019 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
16.
Qiang drives miles at an average speed of miles per hour. How many additional miles will he have to drive at miles per hour to average miles per hour for the entire trip?
Answer: D
Small hint:
The first miles took hour
Big hint:
Set total time equal to total distance divided by
Video solution:
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Written solution:
For the first miles, Qiang drove for an hour.
Let be the distance that Qiang must drive to satisfy the condition. It will take him hours to drive this distance.
The total trip is now miles. We know the average speed is miles per hour, so this will take him hours.
Setting the two times equal to each other, we get
Cross-multiplying and simplifying yields
Thus, the correct answer is D.
Problem 16 in other years
- 1985 AMC 8
- 1986 AMC 8
- 1987 AMC 8
- 1988 AMC 8
- 1989 AMC 8
- 1990 AMC 8
- 1991 AMC 8
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