Audio Fade In/Out

Is it possible to have the audio fade in or fade out slower than the duration of showing 1 slide? For example we show 2 slides for 5 seconds each, audio starting with the first slide but reaching the full volume only after 10 seconds.
Is it possible to rise and lower the volume in the same audio at any point. For example 2 slides with 100 %, next 2 slides with 80 %, next 2 slides with 60 %.