Question 509124
When the daughter was born:

d[0] = 0 
m[0] = d

Now after adding d years.

d[1]  = d
m[1]  = 2d

So we have that the mother is twice as old as the daughter.

If the mother is 36 right now, that means that the daughter is 18.

Then 5 years ago, the daughter was 13. <--- Answer