Question

rebecca ran 21 miles in 5 hours. if she ran at a constant speed, how many miles did she run in 2 hours?

8.4 miles
42 miles
4.2 miles
1.2 miles

Explanation:

Calculate the unit rate of speed

$$ \text{Speed} = \frac{21\text{ miles}}{5\text{ hours}} = 4.2\text{ miles per hour} $$

Calculate the distance run in 2 hours

$$ \text{Distance} = 4.2\text{ miles per hour} \times 2\text{ hours} = 8.4\text{ miles} $$

Answer:

• (A) 8.4 miles (Correct answer)
• (B) 42 miles
• (C) 4.2 miles
• (D) 1.2 miles