The midpoint can be obtained by taking the averages of the x-coordinate and the y-coordinate. The averages obtained are the new coordinates for the midpoint. This is shown below:
x-coordinate:
X = (16 + 28)/2
X = 22
y-coordinate:
Y = (5 + -13)/2
Y = -4
Therefore, the midpoint has the coordinates M (22 , -4)