Final answer:
The Smiths' average speed is 60 miles per hour. Time should be on the x-axis when plotting their speed in miles per hour. The Smiths can travel 600 miles in 10 hours.
Step-by-step explanation:
a. To find the average speed, we need to calculate the total distance traveled and divide it by the total time taken. In this case, the Smiths traveled 60 miles in the first hour and another 60 miles in the second hour, giving a total distance of 120 miles. The total time taken is 2 hours. Therefore, the average speed is 120 miles / 2 hours = 60 miles per hour.
b. If we were to plot their speed in miles per hour on a coordinate plane, we would put time on the x-axis. Time is the independent variable, while speed is the dependent variable.
c. To plot their speed and cumulative time for the first two hours, we can use the coordinates (1, 60) and (2, 120). We can continue the pattern by adding another point at (3, 180) if we have information about their speed for the third hour.
d. To estimate how long it would take for them to travel 300 miles, we can use the concept of average speed. Since their average speed is 60 miles per hour, we can divide the total distance (300 miles) by the average speed: 300 miles / 60 miles per hour = 5 hours.
e. To find out how far they can go in 10 hours, we can multiply their average speed by the total time: 60 miles per hour * 10 hours = 600 miles.