Question 964684
We want the Probability (X < 300)
First calculate the z-score 
z-score = X - mean / std dev = (300 - 268) / 15 = 2.133333333 approx 2.13
now consult the table of z-scores for the probability associated with a z-score of 2.13
Probability (X < 300) = 0.9834 approx 0.98