Notez cu ,,a " numarul gastelor
2 × a + a / 2 + a / 4 + 1 = 100
2 × a + a / 2 + a / 4 = 100 - 1
4 × 2 × a + 2 × a + a = 4 × 99
11 × a = 4 × 99 l : 11
a = 4 × 9
a = 36 gaste
Verific:
36 + 36 + 36 : 2 + 36 : 4 + 1 = 100
= 72 + 18 + 9 + 1 =
= 90 + 10 =
= 100