The x coordinate will be 3 + 1/(4 + 1) * (the positive difference of the x coordinates) , and the y coordinate will be 2 + 1/(4 + 1) * (the positive difference of the y coordinates)
x coordinate = 3 + 1/5(8 - 3) = 3 + 5/5 = 4
y coordinate = 2 + 1/5(15 - 2) = 2 + 13/5 = 4.6
So the new coordinates are ( 4 , 4.6 )