seven years ago, Gerry was half as old as Celine is now. In ten years, he will be 4/5 as old as Celine will be. How old are they?
Let g=gerry
c=celine
g-7=1/2(c+7)
g+10=4/5(c+10)
Solve for g and c
c=celine
g-7=1/2(c+7)
g+10=4/5(c+10)
Solve for g and c