Answer:
The probability that more than half of the sample would vote for him is P=0.7549.
Explanation:
With a sample size of n=300, we can approximate this to the normal distribution.
The parameters will be

We have to calculate the probability that half or more of the sample vote for him. This is P(x>150).
To calculate this probability, first we calculate the z-value:

Then

The probability that more than half of the sample would vote for him is P=0.7549.