Question

The speakers are incoherent (answer in multiples of given intensity of speakers)

Answer 1

Since, $I_o$ is the intensity of each speaker. So maximum intensity is $4I_o$ and minimum intensity is $0$ in interference pattern.
Also, as the speakers are incoherent. So, both destructive interference and constructive interference takes place continously at a point P at different instant of time. Hence a sound of average intensity $2I_o$ is heard.