When source of light (here its a star in the given question) receds that means when source and observer moving away from each other or source is moving away from observer or observer is moving away from source then apparent wavelength increases. This is called Red shift.
Since the wavelength of spectral line which atom emitts in lab is 400 nm and which due to star is found to be 410 nm means star is moving away from the earth.
Speed of star moving away from the star can be calculated using the formula of Doppler's effect in light.
Calculation is shown following..
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