t-vârsta tatei
m-vârsta mamei
x-vârsta unui fiu
y-vârsta celuilalt fiu
|........t..........|
|......x+y......||.....10...|
|......m......||.....4....|
|....x...|
|..y..||..2..|
t+m+x+y=100
t+t-4+t-10=100
3t-14=100
3t=100+14
3t=114
t=114:3=38
m=38-4=34
x+y=38-10
x+y=28
y+2=x
x+2+y=28
2y+2=28
2y=28-2
2y=26
y=26:2=13
x=13+2=15