You can put this solution on YOUR website! Grandfather is 66 years old and his eldest daughter is 28.
When will grandfather be twice as old as his oldest daughter?
:
Let y = no. of years for this to be true
66 + y = 2(28+y)
66 + y = 56 + 2y
66 - 56 = 2y - y
10 = y
this will be true in 10 years
:
Gramps will be 76 and Daughter will be 38