Help With AP Physics B?

The total time taken for the ball to travel down the alley is split between the time taken for the speed of sound travelling that distance and the time taken for the ball to reach to the pins. The time taken for speed is t = 16.5/340 = 0.0485 s. The time for the ball travelling down the alley is 2.5 - 0.048 = 2.415 s. Speed is then v = 16.5/2.4515 = 6.73 m/s