Given :
During a football game, Freddie loses 10 yards on the first down and then gains 7 yards during the second down.
On the third down, Freddie loses 1 yard.
To Find :
What does Freddie need to do on the fourth down to make his team be back where they were when they started.
Solution :
Let, yards gain is +ve and yards loses is -ve.
So, yards loses in first down, d1 = -10 .
Yards gain in second down, d2 = 7 .
Yards loses in third down, d3 = -1 .
Let, number of yards travelled in fourth down is x.
So, -10 + 7 -1 = x
x = -4 yards.
Therefore, Freddie need to move 4 yards to return to the started position.
Hence, this is the required solution.