Answer: -20 yards
Explanation:
Given : Bobby’s football team received four five-yard penalties in the first quarter.
i.e. Number of five-yard penalties in the first quarter =4
It meant his team lost yardage in their progress toward the goal line.
Then, the change in their progression down the field as a result of these penalties :

Hence, the change in their progression down the field as a result of these penalties = -20 yards