There is a family of six persons A, B, C, D, E and F. Their professions are Lawyer, Doctor, Teacher, Salesman, Engineer and Accountant (one profession each). There are two married couples in the family. D, the Salesman, is married to the lady who is the Teacher. The Doctor is married to the Lawyer. F, the Accountant, is the son of B and brother of E. C, the Lawyer, is the daughter-in-law of A. E is the unmarried Engineer. A is the grandmother of F. How is E related to F?

Introduction / Context:

This is a combined blood-relation and logical assignment puzzle. It involves six family members, six different professions and two married couples. We have to use all the clues to reconstruct the family tree and then decide how E is related to F. The final twist is that even after determining they are siblings, the exact gender of E is not fixed, so we must check whether the relation is uniquely determined.

Given Data / Assumptions:

• Family members: A, B, C, D, E and F.
• Professions: Lawyer, Doctor, Teacher, Salesman, Engineer, Accountant (all different).
• D is the Salesman and is married to the lady who is the Teacher.
• The Doctor is married to the Lawyer.
• F is the Accountant, the son of B and brother of E.
• C is the Lawyer and is the daughter-in-law of A.
• E is the unmarried Engineer.
• A is the grandmother of F.
• There are exactly two married couples in the family.

Concept / Approach:

We first assign professions and marriages. Then we identify parent–child relations using the clues about daughter-in-law, grandmother and son. This will show that E and F are siblings. Finally, we check whether we can determine E's gender from the information. If we cannot, we cannot choose “brother” or “sister” with certainty, leading us to the “cannot be determined” option.

Step-by-Step Solution:

Verification / Alternative check:

The complete consistent picture is: A is grandmother and Teacher (and married to D, the Salesman); B is the Doctor and child of A; C is the Lawyer and B's wife (A's daughter-in-law); E is the Engineer, an unmarried child of B and C; F is the Accountant, the son of B and C. In this model, E and F are brother and sister or possibly two brothers or a brother and a sister, depending only on E's gender, which is not specified. Thus, all clues are satisfied without fixing whether E is male or female.

Why Other Options Are Wrong:

“Brother” assumes E is male, but the problem never states that; only F is explicitly identified as a son (male).

“Sister” assumes E is female, which again is not stated anywhere in the clues.

“Cousin” is wrong because E and F clearly share a parent B and a parent C, making them siblings rather than cousins.

Common Pitfalls:

Many students correctly deduce that E and F are siblings but then rush to pick “brother” because the word “Engineer” might unconsciously sound masculine. Logical puzzles, however, never rely on stereotypes for gender; they require explicit information. When gender is unspecified, you cannot fix the relation as brother or sister.

Final Answer:

The exact relationship (brother or sister) of E to F cannot be determined from the given information.