There are 720 permutations of the digits 1, 2 ,3 , 4, 5, 6 suppose these permutations are arranged from smallest to largest numerical values beginning from 123456 and and ending with 654321.Whihc of the following is correct?
Number on the 124th position is 213564
Number on the 267th position is 321546
Number on the 124th position is 213546
Number on the 267th position is 321564
It can be obtained by Starting from 1 = 5! = 120

In the given circuit diagram, $I_L = 5$ mA and the Zener voltage is $V_Z = 5$ V. If $i_z = 4 i_L$, find the value of $R_s$ (in $\Omega$). 

Three silicon diodes connected parallel to each other as shown. Forward voltage of diode is 0.7 V. Find current through diode A : 