Question 51618
Well the Grandfater's age is self-explanatory along with the dad's and the son's.  So here's how we figure out the rest.  45x2=?  and 45x2 comes out to ninety.  The closest sqare root to the grandma's age that is higher is 10x10 equals 100.  So one hundred minus 90=the daughters age which is ten and the midpoint between ten and ninety is 50.  here is a chart.

Son=13
Dad=45
Grandfather=87
Daughter=10
Mom=50
Grandmother=90