Răspuns:
5 +10+15+... +525 =
5( 1+2+3+....+105) = 5 ( 105 ×106÷2)= 5×5565= 27825
3+6+9+....+315= 3( 1+2+3+...+103)
= 3× ( 103× 104 ÷2)= 3×5356= 16068
27825/ 16068 = simplificam prin 3
= 9275/ 5356
