How can i run audio from a tape monitor stero output across the house to computer speakers? RCA wire/jack?

Here's the bottom line: RCA plug output from stereo in the living room, connect somehow to powered speakers with 3.5mm audio plug input in the kitchen. I've gotta figure out what: cable, wallplates, and connectors to use. Running the cable isn't a big problem.
Can't I just use a y connector to switch from 3.5 to RCA? And which cable is preferable for a 60-foot run? Thanks in advance!

If you check the 3.5mm jack, it should basically have 3 contacts, the extreme is chanel A (i.e. right), the next is channel B (i.e. left) and the last big one is ground.
In your stereo you have two RCA, one is channel A with groung the other is channel B with ground.
You need just to purchase a female stereo 3.5mm jack and 2 male RCA. Wire it so Channel A in the 3.5mm goes to Channel A (the tip) in one RCA, then Channel B in the 3.5mm to the tip in the other RCA. The grounds are common, just wire them so they are all connected together.
This should be easy, you'll figure out....