Projectile Motion, Please HELP ASAP

[vcantu04]

the girl always throws the toys at an angle of 30 from point a as shown. Determine the time between throws so that both toys strike the edges of the pool B and C at the same instant.
With what Speed must she throw each toy?

.25m is the height of the pool.

I don't know how to start since I don't know the initial velocity or time in the air. I will appreciate if somebedy could give a solution or hints to this problem. thanks. Also I do not know which equations to use since we didn't cover them in class.

 

[Guest]

Are you sure that no further information was given for this problem?

Equations that may be required are:

v^2 = u^2 + 2as
v=u +at
s=ut + (1/2)at^2

where v - final velocity
u- initial velocity
t - time
s - displacement
a- acceleration

also need to resolve the velocity into horizotal(cos) and vertical(sin) parts.