# Difference between revisions of "2020 AMC 8 Problems/Problem 11"

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We use the formula <math>\text{speed}=\dfrac{\text{distance}}{\text{time}}</math>. Naomi's distance is <math>6</math> miles, and her time is <math>10</math> minutes, which is equivalent to <math>\dfrac{1}{6}</math> of an hour. | We use the formula <math>\text{speed}=\dfrac{\text{distance}}{\text{time}}</math>. Naomi's distance is <math>6</math> miles, and her time is <math>10</math> minutes, which is equivalent to <math>\dfrac{1}{6}</math> of an hour. | ||

+ | Since speed is distance over time, Naomi's speed is <math>36</math> mph. | ||

+ | Using the same process, Maya's speed is <math>12</math> mph. Subtracting those, we get an answer of <math>\boxed{E) 24}</math> |

## Revision as of 23:59, 17 November 2020

## Problem 11

After school, Maya and Naomi headed to the beach, miles away. Maya decided to bike while Naomi took a bus. The graph below shows their journeys, indicating the time and distance traveled. What was the difference, in miles per hour, between Naomi's and Maya's average speeds?

## Solution

We use the formula . Naomi's distance is miles, and her time is minutes, which is equivalent to of an hour. Since speed is distance over time, Naomi's speed is mph. Using the same process, Maya's speed is mph. Subtracting those, we get an answer of