Răspuns:
2. Ana+Aurel=80 lei
Ana=3xAurel
=> 3Aurel+Aurel=80lei
=> 4Aurel=80
=>Aurel= 80÷4=20 lei
=> Ana+20=80
=>Ana= 80-20
=>Ana= 60 lei
3.a+b=32
a=b:7
=> b:7+b=32
b/7 +7b/7= 224/7
8b=224
=>b=224:8
=>b=28
=> a=28:7
=>a=4
4.Rigla costa 24 de lei,iar compasul de 5 ori mai mult decat rigla.Cat costa compasul?