2014 AMC 10B Problem 3

Attempt Problem 3 of the 2014 AMC 10B 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 2014 AMC 10B solutions, or check the answer key.

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3.

Randy drove the first third of his trip on a gravel road, the next 2020 miles on pavement, and the remaining one-fifth on a dirt road. In miles, how long was Randy's trip?

30 30

40011 \dfrac{400}{11}

752 \dfrac{75}{2}

40 40

3007 \dfrac{300}{7}

Answer: E
Concepts:fractionlinear equation
Difficulty rating: 900
Solution:

Let the path distance be t.t. Then, we get: t=t5+20+t3t=20+8t15715t=20t=3007.\begin{aligned}t &= \dfrac t5 + 20 + \dfrac t3 \\ t &= 20 + \dfrac {8t}{15} \\ \dfrac 7{15} t &= 20\\ t &= \dfrac{300}7.\end{aligned}

Thus, the correct answer is E .

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