Games : How ping is measured between two players with different ping times?

Say i have a ping of around 34-36 to my ISP and my friend gets like for example 47ms, so if we got a different latency time from the same ISP and in the same town, if i\he host a match game.. what do you think pinging each other would look like? is it going to look like this 47+34=81ms? or is it going to be different? Recently i played with my neiborhood friend and i got 39-41ms to him which is only 4-7ms difference when pinging to my ISP

hope you guys can answer that question, and Thnx for answering.

Best regards.

John Hark.