So Confused

A parallel plate capacitor is made of two 3.0 cm x 3.0 cm square plates that are separated by 1.0 mm are connected to a12.0 V battery. If and electron is released from the negative electrode, what speed will it reach by the time it arrives at the positive...

Find the equation of variation in which y varies jointly as x and z and y=8, x=4 and z=2