In this question,
Sasha runs 2 miles during each track practice. Therefore, the length of each track = l = 2 miles
Shasha needs to run 4 miles. Therefore, the total distance would be = d = 4 miles.
We have to calculate the number of tracks = n
The total distance can be calculated by multiplying the number of tracks with the length of each track. Therefore,
d = n * l
Now, put the values in the equation
4 = n * 2
4/2 = n
2 = n
or
n = 2
Hence, Sasha needs 2 tracks to run 4 miles.