Let take the number be 600851475143, so to find the largest prime factor run the following code
Result : 6857
<?php
$max = 600851475143;
$l_num = 0;
for ($j = floor(sqrt($max)) / 2; $j >= 2;...
The following combinations can be obtained:
(i) The individual resistances: 2Ω,3Ω,6Ω
(ii) All in series: 11Ω
(iii) All in parallel: 11Ω
(iv) Three different possible mixed grouping of resistors:4Ω,9/2Ω36/5Ω