as for the second question...
it is easy also...
just you remember that the intensity is proportional to A2 (i mean the square of the amplitude...)
now you can claim that I1/I2 =1.001
now I1=power/4pi (r1)2 and I2= the same power/ 4 pi (r2)2
but notice here that r2-r1 = lambda (successive fronts) so that you can substitute for this...
now how to evaluate lambda????? just you have 660hz and velocity of light 330m/s and you construct your answer...
i think it is enough for these questions
thanks a lot