Use section formula (x,y)=(mx2+nx1/m+n,my2+ny1/m+n) in which m:n are the ratio and (x1,y1) and (x2,y2)
are the points.
Let k:1
Substituting the values from the points mentioned above to (mx2+nx1/m+n,my2+ny1/m+n) gives
(11,y)=(9k+15 / k+1,20k+5 / k+1)
Equate first component to get ratio:
9k+15 / k+1=11
9k+15=11k+11
2k=4k
k=2
22:1
Do the same for the second to get the value for y:
Calculation:
y=20×2+5 / 2+1
=45/3
y=15
-Vinculum