A+B+C+D=162
B=A+1
D=C+1
D=A+21 => C+1=A+21 |-1 => C=A+20 ( |-1 adica scadem din fiecare 1)
Inlocuim ce am aflat in ecuatie.
A+A+1+A+20+A+21=4xA + 1+20+21=4xA+42
4xA+42=162 => 4xA=162-42 => 4xA=120 => A=120:4 => A=30
Acum ca am aflat A putem sa le aflam si pe celalalte.
A=30
B=A+1 => B=30+1 => B=31
C=A+20 => C=30+20 => C=50
D=A+21 => D=30+21 => D=51
30+31+50+51= 61+101=162
Sper ca intelegi asa. Succes