Q.

Two number k1 and k2 are randomly chosen from the set of natural numbers. Then, the probability that the value of ik1+ik2, (i=–1) is non-zero, equals          [2025]

1 23  
2 12  
3 14  
4 34  

Ans.

(4)

Given, ik1+ik2≠0

Possible values of ik1= 4 = Possible values of ik2

∴  Cases are i, –1, – i, 1

∴  Total number cases =4×4=16

For ik1+ik2=0,

Cases are (1, –1), (–1, 1), (i, – i), (– i, i)

∴  Required probability =1–416=1216=34.