Calculating time in physics equation?

Time = distance/ speed

For example if the speed is 0.2m/s, the time to travel 0.15m is

t = 0.15/0.2 = 0.75s

But you haven't given the speed!

Find the average speed for each case and T = S/Vavg where S is each distance traveled at that average speed.

As you've given us nothing to indicate Vavg for each datum, we can't give you a specific answer. But if we make the assumption that the ball is dropped from those heights S = .15, .2, and .25, we know that Vavg = gT/2 discounting air drag effects (which we can do at these heights). g ~ 9.8 m/s^2 near Earth's surface.

So S = Vavg T = aT/2 * T = 1/2 gT^2 and T = sqrt(2S/g) = ? for each case. ANS.

V=d/t where v is velocity to is time and d is distance

You need the speed of the ball bearing

Not clear this question

Do you mean : in a free fall???

If so, then t = sqrt(2h/g)

Plug and chug

i agree with steve4physics.