This is true because:
the ratio 2 to 3 = 2:3
Is equivalent to :
2/(3+2) = 2/5
If you want to express a ratio a:b as a fraction, you can always use this formula:
a:b = a/(a+b)
You can use the following formula:
If d(xp,yp) divides a line segment form A(x1,y1) to B(x2,y2) in the ratio a:b, then:
xp = x1 + a/(a+b) * (x2 - x1)
yp = y1 + a/(a+b) * (y2 - y1)
So:
xp = 1 + 2/5*(16-1) = 7
yp = 4 + 2/5*(14 - 4) = 8