Question

Brian ran a 5-kilometer race in 40 minutes. How far did he run in 18 minutes? Write your answer as a decimal and do not round.(1 point)
$$

1 answer

To determine how far Brian ran in 18 minutes, we first need to find his running speed.

  1. Calculate Brian's speed:

    • Brian ran 5 kilometers in 40 minutes.
    • His speed \( v \) in kilometers per minute is calculated as: \[ v = \frac{\text{distance}}{\text{time}} = \frac{5 \text{ km}}{40 \text{ minutes}} = \frac{5}{40} = \frac{1}{8} \text{ km/minute} \]
  2. Calculate the distance covered in 18 minutes:

    • The distance \( d \) Brian covered in 18 minutes can be calculated using the formula: \[ d = v \times \text{time} = \left(\frac{1}{8} \text{ km/minute}\right) \times 18 \text{ minutes} \]
    • Multiplying these values gives: \[ d = \frac{1}{8} \times 18 = \frac{18}{8} = \frac{9}{4} = 2.25 \text{ km} \]

Thus, the distance Brian ran in 18 minutes is:

\[ \boxed{2.25} \]