With what velocity an observer sould move relative to a stationary source so that he hears a sound of double the frequency of souce?

An observer is moving towards the stationary source of sound, then

With what velocity should an observer approach a stationary shound source so that the apparent frequency of shound should appear double the actual frequency ? (v is velocity of shound).

An observer moves towards a stationary source of sound. The percentage change in the apparent frequency is

What should be the velocity of a sound source moving towards a stationary observer so that apparent frequency is double the actual frequency (Velocity of sound is v )

An observer moving towards a stationary source observes that the apparent frequency is three times the actual frequency of the source. If the velocity of sound is V, the velocity of the observer would be-

An observer approaches a stationary sound source 1000 Hz at twice the speed of sound. What frequency does the observer hear?

At what speed should a source of sound move away from a stationary observer so that observer finds the apparent frequency equal to half of the original frequency?