Final answer:
By using the concept of speed, distance, and time and by setting up a proportion based on the given information, we can determine that his friend's house is 1.9 miles away. Option A is correct.
Step-by-step explanation:
To find the distance to his friend's house, we need to use the concept of speed, distance, and time. Alex skateboards at a constant speed from his house to school which is 3.8 miles away and it takes him 18 minutes. Since he skates at the same constant speed to his friend's house and it takes him 9 minutes, we can set up a proportion to find the distance.
Let x be the distance to his friend's house. We can set up the proportion:
3.8 miles / 18 minutes = x miles / 9 minutes
Cross-multiplying gives us:
18x = 3.8 * 9
18x = 34.2
x = 34.2 / 18
x = 1.9
Therefore, his friend's house is 1.9 miles away. Option A is correct.
Complete question:
Alex skateboards at a constant speed from his house to school . miles away. It takes him minutes.
After school, Alex skateboards at the same constant speed to his friend's house. It takes him 9 minutes. How far away is his friend's house?
A. 1.9 miles
B. 3 miles
C. 4.5 miles
D. 6 miles