The average of 35 numbers is zero. of them, at the most, how many may be greater than zero?
⇒ (x1 + x2 + x3 + .......+ x_{36})/36 = 0
⇒ x1 + x2 + x3 + .......+ x_{36} = 0
⇒ x1 + x2 + x3 + .......+ x_{35} = - x_{36}
It means Atmost 35 number is greater then zero.
∴ 35 numbers can be greater than zero.
Answer: 35