Follow this very simple pattern, EVERY time.
#1 Name Stuff.
#2 Name What?
#3 What Does It Want?
#4 Name That!
"how old is she now ?"
That is what it wants. Name it. Write it down.
J = How old Jenny is now.
After that VERY important step, the rest is a translation problem.
"Jenny lived half her life in california"
"one third of her life in new york."
"she has lived in Florida for four years"
"how old is she now ?" J!!!! We defined that earlier.
J = J/2 + J/3 + 4
Solve for J.
Every time. Trust me on this.