Question

Savannah can bicycle 54 miles in the same time as it takes her to walk 18 miles. She can ride 9 mph faster than she can walk. How fast can she walk?

a) 9 mph

b) 6 mph

c) 3 mph

d) 12 mph

Answer 1

Upon setting up the equations based on the relationship distance = speed × time and solving for Savannah's walking speed, we find it to be 4.5 mph. However, that answer is not among the options provided, suggesting a possible error in the question or the options.

Step-by-step explanation:

To solve for Savannah's walking speed, let's denote Savannah's walking speed as w miles per hour (mph). Since she rides 9 mph faster while biking, her biking speed would be w + 9 mph. We know that the time to bike 54 miles and to walk 18 miles is the same. We can set up the following equations based on the relationship distance = speed × time:

• Time to bike 54 miles = 54 / (w + 9)
• Time to walk 18 miles = 18 / w

Since the times are equal, we can set the two expressions equal to each other and solve for w:

54 / (w + 9) = 18 / w

Cross-multiplying gives us:

54w = 18(w + 9)

Dividing both sides by 18:

3w = w + 9

Subtracting w from both sides:

2w = 9

Dividing by 2 gives:

w = 4.5

Therefore, Savannah's walking speed is 4.5 mph, which is not one of the options provided. There may be an error in the question or the options.