CAT Exam Model Paper 4 with solutions for free online practice

If Statement III made by Billu and Chiklu are not true then in that case both Amar and Billu will be having the blue ball which is not possible. Hence, Amar’s third Statement is definitely not true.
If we assume that Billu’s 3rd Statement is also not true (and hence Chiklu’s is true), the arrangement will be:

If we assume that Chiklu's 3rd Statement is not true (and hence Billu’s is true), the arrangement will be:

Hence, it cannot be determined.