I am not sure whether this is a math problem. <may be is probability>
5 person A, B, C, D, and E each bought a lottery ticket. Only one of them strikes the lottery.
A said: C strikes the lottery
B said: A strikes the lottery
C said: A is lying
D said: I did not strike the lottery
E said: B strikes the lottery
Only one of them tells the truth. Who strikes the lottery?
Oops , i made a mistake .
Or maybe we can try elimination .
If A strikes , then C and D are telling the truth
If B strikes , then C , D and E are telling the truth
If C strikes, Then A and D are telling the truth
If D strikes , Only C tells the truth
If E strikes, then C and D are telling the truth .
It says that only one tells the truth and only one strikes .
Thus D strikes a lottery and C is telling the truth .