Thank you for using the site. I'll be happy to help you with this problem.
Since the population standard deviation is known, you can use the z-statistic for this problem. The z-value is:
z = (60,000 - 63,500) / (6,100 / sqrt(35)) = -3.39
The probability is then P(x < 60,000) = P(z < -3.39) = 0.0003.
Please feel free to ask if you have any questions about this solution.