Question 459668
u=me
m= mother
n= grandmother
g= great grandmother
m=u+21
n=m+21
g=n+21
10y+x=u
10x+y=g
We also know that 
y > 0 and y < 10
x > 0 and x < 10
g < 100
There are two possible solutions
g = 81,n = 60,m = 39,u = 18,x = 8,y = 1
g = 92,n = 71,m = 50,u = 29,x = 9,y = 2
check