Răspuns :
numerele prime de forma 1x∈[11,13,17,19];⇒x∈[1,3,7,9];x∈N,x-numar prim;
⇒11+13+17+19
⇒11+19+13+17[asociativitate]
⇒30+30
⇒30·2=60;
⇒11+13+17+19
⇒11+19+13+17[asociativitate]
⇒30+30
⇒30·2=60;
Numarele prime de forma 1x=11 , 13 , 17 , 19
Suma acestora 11+13+17+19 = 60 .