Three working women have different careers. If only one of statements 1, 2 and 3 are true, can you tell whether or not Mary is a nurse? 1. This statement is only true if statement 5 is false. 2. This statement is true if statements 4 or 5, or both 4 and 5 are true. 3. This statement is false only if both statements 6 and 1 are true. 4. Mary is a nurse 5. Karen is an artist. 6. Sarah is a photographer.