The question can be solved using conservation of linear momentum.
= 0.06kg and
= 0.03kg
Let the initial velocity of Marble A be , = 0.7m/s
Let the initial velocity of Marble B be, = 0m/s
Let the velocity of Marble A after collisiong , = -0,02m/s
Let the velocity of Marble B after collision be
From the conservation of linear momentum equation. We get,
Substituting the values we get,
(0.06)(0.7) + 0 = (0.06)(-0.02) + (0.03)
we get, = 1.44m/s