probability for over booked pasangers on a flight.

Convoy Airlines has recently instituted a policy of booking 400 passengers for a flight on an airplane that only has a capacity of 350. Recent studies show that only 75% of passengers booked for a particular flight actually arrive for the flight. What is the probability that if Convoy Airlines books 400 passengers for a particular flight that not enough seats will be available?

The answer i came up with is 1.06 which i think is wrong.

I used the binomial formula nCx (p)^x (q)^n-x to solve this problem, can some one help me with this.