For a normal distribution with a mean of 16 and a standard deviation of 3, find the 50th percentile. can someone explain how to solve this.

The probability distribution of normal distribution is given by,

f(x) = 

Where a = mean = 16 and α = standard deviation = 3

In normal distribution, skewness is zero. That is, distribution is symmetric. 
Therefore, mean, median and mode coincide at a point in case of normal distribution.

50th percentile is same as median or mean or mode
Therefore, 50th percentile = 16