Question

) four friends have been identified as suspects for an unauthorized access into a computer system. they have made statements to the investigating authorities. alice said "carlos did it." john said "i did not do it." carlos said "diana did it." diana said "carlos lied when he said that i did it." (a) if the authorities also know that exactly one of the four suspects is telling the truth, who did it? explain your reasoning. (b) if the authorities also know that exactly one is lying, who did it? explain your reasoning

Answer 1

Answer of part (a):

As a matter of first importance we see that Carlos and Diana can't be both lying. On the off chance that Carlos is lying, at that point Diana would come clean, and if Carlos is coming clean, at that point Diana would lie. So it is either Carlos or Diana who is coming clean. John is lying, and John said "I didn't do it" Therefore John had the unapproved access.

Answer of part (b):

Again we see that Carlos and Diana can't be both coming clean, so the liar is either Carlos or Diana. This implies Alice is coming clean. Alice stated: "Carlos did it"Therefore it was Carlos who had the unapproved get to.