Does more cores add higher clock speed?

A guy is saying that 800 Mhz dual core processor in iPhone 4S is at 1.6 Ghz. He says that 800 Mhz x 2 cores = 1, 6 Ghz. I know this can't be right.

No

More cores increases the processing power in megaflops.
Increasing the clock speed increases the power dissipation more than adding cores, which is partly why there are multicore processors now - a single core with the same performance would melt.

Manufacturers have reache dthe physical limit of die size and speed, multi core is currently the only way they can go but it isn't a new idea, motherboards were available in the 90s with two sockets for two processors but the software wasn't up to it, two cores doesn't double the speed but can double the data handling IF the software is written for it

Each core does has its own speed, Yes they have their own set speed, but it doesn't necessarily mean that they add up, because they don't. When there are multiple cores it just makes it easier for you to multitask because it spreads the work load out. That is why you are able to do many more things and run multiple task on the new computers and phones. For example I have a AMD quad core processor at 3.1 ghz per core. But my processor speed is still only rated at 3.1 ghz. The other cores are only used when there's alot of work being done. Another example is gaming, most of the time unless you are running a rediculously powerhoused visual game, 2 cores will only be used instead of all 4. I take it the guy you talked to must be a salesman? I actually had this belief at one time too, I even asnwered a question about it and said the same thing, but I just like you thought about it for a second and realized that it just didn't make sense. Thats when I thought about my own computer and said the same because as I answered earlier, my processor was rated at 3.1ghz, but each core was rated at 3.1ghz. I did research and sure enough what I answered to you is what I found.