Question 388958
a,b,c,d = Siblings
{{{a+10+b+10+c+10+d+10=100}}} ------- Plus Ten due to "In ten years"
{{{a+b+c+d+40=100}}}
{{{a+b+c+d=60}}}

{{{a+b+c+d+28=x}}} ------- "plus 7 years"
{{{40+28=x}}} ---- a+b+c+d=40
{{{68=x}}}
So in 7 years their added ages will be 68