Answer: 4 miles.
Explanation:
Let's use the rectangular coordinates (x,y)
And define:
East as the positive x-axis.
North as the positive y-axis.
We know that, if the jogger starts at the point (0mi, 0mi):
"Runs 3 miles East"
Then the new position is (3mi, 0mi)
"Then 7 miles west"
The new position is (3mi - 7mi, 0mi) = (-4mi, 0mi)
Now, the displacement is calculated as the difference between the initial position and the final position, and this can be written as:
D = I (-4mi, 0mi) - (0mi, 0mi)I = √( (-4mi - 0mi)^2 + (0mi - 0mi)^2) = 4mi
The total displacement is 4 miles.
