a + b + c = 33
b = a-2 => a = b + 2
b = c+2 => c = b - 2
Deci a + b + c = 33 => (b+2) + b + (b-2) = 33 => b + 2 + b + b - 2 = 33 => 3b = 33 =>
=> b =11 => a = 11 + 2 => a = 13
=> c = 11 - 2 => c = 9
Deci 13 mere in primul cos, 11 mere in al doilea cos si 9 mere in al treilea cos.