Help with one 2-D kinematics problem? Answer is off by 2

[RyanJF]

Homework Statement

"A motorcycle daredevil is attempting to jump across as many buses as possible. The takeoff ramp makes an angle of 18 degrees above the horizontal, and the landing ramp is identical to the takeoff ramp. The buses are parked side-by-side, and each bus is 2.74 m wide. The cyclist leaves the ramp with a speed of 33.5 m/s. What is the maximum number of buses over which the cyclist can jump?"

A = 9.8

Homework Equations

Kinematics equations

The Attempt at a Solution

First thing I knew I had to do was find the original velocity in the X-component. To solve for this, I did:

Vx = Cos18 * 33.5 = 31.86 m/s
Vx, Vox = 31.86 m/s

In order to use a distance equation, I knew that it was necessary to solve for time. I used the following equation, substituting overall distance with the distance of one bus:

T = sqrt(2x/a)

T = sqrt(2*2.74/9.8)

T = .75 sec

Then I selected one of the kinematics equations for distance in the x:

Xx = VoxT + 1/2 * 9.8 * t^2

Xx = (31.86 * .75) + 1/2 * 9.8 * .75^2

Xx = 26.65

I assumed that since "T" represented the time it took to jump one bus, that the numerical conclusion of the above equation would equal the number of buses able to be jumped by the daredevil.

However, the "answer section" in the back of the book says that the cyclist can jump only 24 buses, which would be 2-3 buses less than what I got, depending on which way you decided to round.

Can somebody please show me what I'm doing wrong? I have a test tomorrow and while I don't like to blame things on the teacher, a lot of people have been saying that he doesn't explain things too thoroughly, and I'd prefer to keep my 100%.

EDIT:

I've been trying to learn this from the book. The only review we got from the teacher were a bunch of really irrelevant questions.

 

[RyanJF]

I don't know whether or not my answer is still incorrect, but I've realized that results presented in my book do not match up with results presented by my calculator - I was working through an example problem, and I'm quite sure that the work done in the book was not right... =\

Or maybe my calculator is messed up. One of the two.