Answer to Circuit # 2
Rt = R1 * R2 / R1 + R2
Give arbitrary values to each resistance, for example 100 Ohms each. Find a parallel pair and evaluate:Example 2 parallel resistor [Items 1 & 2] 100 Ohms each equals 50 Ohms, that is 100 Ohms divided by 2 resistors. Now add that value to the next...