What are series and parallel resistances and how do you solve for them?

Question

What are series and parallel resistances and how do you solve for them?

Answer 1

Series resistors are connected in a straight line one after the other and you add the resistances together for a total. Parallel resistors are connected 'side by side' and if you have 3 resistors, each of 15 ohms the equivalent resistance is 5 ohms which comes from 1/15 + 1/15 + 1/15

Answer 2

In series

R= R1 + R2 +......Rn

In Parallel

R= 1/R1 + 1/r2