The z-score for a weight of 336.7g is found as follows;
[tex]z=\frac{336.7-340}{1.5}=-2.2[/tex]
The cumulative probability for a z-score of -2.2 can be found from a normal distribution table:
The cumulative probability for a z-score of -2.2 is 0.0139.
Therefore the answer is 1.39%.