The rate of loss of mass by star X is 1.0 10 -13 M / year. The density of the particles emitted at the

The rate of loss of mass by star X is 1.0 × 10^-13 Mʘ / year. 

The density of the particles emitted at the distance r = 4 U.A. from star-emitter is 4.0 × 10^-17 kg * m^-3.

Calculate the speed of the stellar wind at distance r from the star