Answer
$$v = 2.42\times 10^{-2}m/s$$
Work Step by Step
According to De Broglie, wavelength of particle moving at a velocity v is given by
$$\lambda = \frac{h}{mv}$$
where m is the mass of the particle.
$$\therefore v = \frac{h}{m\lambda}$$
$$v = \frac{6.626\times 10^{-34}}{9.109\times 10^{-31}
\times 3\times 10^{-2} } = 0.0242m/s$$
$$v = 2.42\times 10^{-2}m/s$$
