Question 1155109
The problem does not show enough information to account for "his children" and does not show enough to account for "her grandchildren".  The problem is very poorly written.


If "child" instead of "children", then 
G for Gabe
L for Laur
g for Gabe's child
x for Laur's child
You could make  {{{system(G=g+20,L=x+40)}}}, and then  {{{g+x=230}}}.