I've ran into a slight confusion.
The equation for resistance in a parallel circuit should work for any number of resistors, I assumed. So when I'd have 2 resistors in parallel, total Rt would be: Rt = 1/G and G=1/Ra + 1/Rb
Now my book says, for 2 resistors in parallel, you may use this formula too: Rt = (Ra * Rb) / (Ra + Rb)
When I fill in 100 Ohms for Ra, and 220 Ohms for Rb, the two equations produce different results. (68.75 for the first, and 66.67 for the second). Now, I have tried it with several sets of values, but I couldn't reproduce this difference with those.
What is happening!? I'm lost!
Edit: Yeah, I've been miscalculating indeed. How embarrassing to find out this way. Thanks for all your answers :)