Final answer:
To find Masha's biking speed, we need to calculate the average speed by dividing the total distance traveled by the total time taken. Dina travels 20 miles at a speed of 10 mph, so her total time is 2 hours. Masha has 4 miles left when Dina finishes, so her total distance is 16 miles. Using the formula for average speed, Masha's biking speed is calculated as 8 mph.
Step-by-step explanation:
To find Masha's biking speed, we can use the concept of average speed. Average speed is defined as the total distance traveled divided by the total time taken.
In this case, Dina travels the entire 20 miles while Masha still has 4 miles left to bike. We know that Dina's biking speed is 10 mph.
Since Dina travels the entire distance, we can use the formula for average speed: Average speed = Total distance/Total time.
For Dina, Total distance = 20 miles and Total time = 20 miles / 10 mph = 2 hours.
Now let's find Masha's biking speed. We know that Masha has 4 miles left to bike when Dina finishes. So Masha has traveled a total distance of 20 - 4 = 16 miles.
Using the formula for average speed again, we can calculate Masha's biking speed: Average speed = Total distance/Total time. Given that the Total distance is 16 miles and the Total time is 2 hours, we can plug in these values to find Masha's biking speed. Masha's biking speed is 16 miles / 2 hours = 8 mph.