a+b+c+d+e=70
d=2b
e=d-c
a+b+c+2b+2b-c=70
a+5b=70⇔a=70-5b
b=70-5b+2⇔b=72-5b (a,b,c sunt numere pare consecutive)
c=72-5b+2⇔c=74-5b (a,b,c sunt numere pare consecutive)
d=2(72-5b)⇔d=144-10b
e=144-10b-74+5b⇔e=70-5b
70-5b+72-5b+74-5b+144-10b+70-5b=70
430-30b=70⇔-30b=70-430⇔-30b=-360⇔b=360÷30⇔b=12
a=70-60=10
b=12
c=74-60=14
d=144-120=24
e=70-60=10
PROBA
10+12+14+24+10=70