Answer:
20 yards East
Explanation:
The question states he starts at the 50 yard line, and didn't imply that he'd ran for 50 yards already. Effectively, that said 50 yard would not count.
The question proceeded to saying he ran leftwards for 20 yards. This is the distance, or displacement that we would use as the first measurement. Running 20 yards in the Eastern direction.
The question then proceeded again, to saying he ran rightwards for another 40 yard. By so doing, he eclipsed the initial 20 yards he'd ran. And added few more yards..
40 - 20 = 20, meaning, he ran 20 more yards in the rightward direction.
Therefore, his displacement would be 20 yards to his right or say, Eastern direction.