A \(15\,\text{g}\) marble moves to the right at \(3.5\,\text{m/s}\) and makes an elastic head-on collision with a \(22\,\text{g}\) marble. The final velocity of the \(22\,\text{g}\) marble is \(2.0\,\text{m/s}\) to the right, and the final velocity of the \(15\,\text{g}\) marble is \(5.4\,\text{m/s}\) to the left. What was the initial velocity of the \(22\,\text{g}\) marble?