Question

kyle rides his bike 6 miles in 30 minutes. assuming he rides at a steady speed, write a proportion that could be used to determine how long it would take him to ride his bike 15 miles.
a) $\frac{6 \text{ miles}}{30 \text{ minutes}}=\frac{x \text{ minutes}}{15 \text{ miles}}$
b) $\frac{6 \text{ miles}}{30 \text{ minutes}}=\frac{15 \text{ miles}}{x \text{ minutes}}$
c) $\frac{6 \text{ minutes}}{30 \text{ miles}}=\frac{x \text{ minutes}}{15 \text{ miles}}$
d) $\frac{15 \text{ miles}}{30 \text{ minutes}}=\frac{x \text{ minutes}}{6 \text{ miles}}

Explanation:

Step1: Recall proportion concept

Since speed is steady, ratio of distance to time is constant.
The ratio of distance to time for the first - case is $\frac{6\text{ miles}}{30\text{ minutes}}$.
Let $x$ be the time taken to ride 15 miles. The ratio for the second - case is $\frac{15\text{ miles}}{x\text{ minutes}}$.

Step2: Set up the proportion

We set the two ratios equal to each other: $\frac{6\text{ miles}}{30\text{ minutes}}=\frac{15\text{ miles}}{x\text{ minutes}}$.

Answer:

B. $\frac{6\text{ miles}}{30\text{ minutes}}=\frac{15\text{ miles}}{x\text{ minutes}}$