\[\begin{array}{|c|c|c|} \hline 4 & 7 & 9 \\ \hline 8 & 6 & 8 \\ \hline 3 & 7 & 9 \\ \hline 35 & 49 & ? \\ \hline \end{array} \]
Rule by columns: Each bottom entry equals \[ (\text{top})\times(\text{middle})+(\text{bottom of the 3rd row}). \] Check first two columns: \[4\times 8 + 3 = 35\] , \(\quad\) \[7\times 6 + 7 = 49\] . So for the third column: \[ 9\times 8 + 9 = 72 + 9 = 81. \] \[ \boxed{81} \]
A, B, C, D, E, F and G are travelling in three different vehicles: Swift, Creta, and Nexon. There are at least two passengers in each vehicle. Among them, only two are male. There are two engineers, two doctors and three teachers.
(i) C is a lady doctor and she does not travel with A and F, who are sisters.
(ii) B, a male engineer, travels with only G, a teacher, in a Swift.
(iii) D is a male doctor.
(iv) Two persons belonging to the same profession do not travel in the same vehicle.
(v) A is not an engineer and travels in a Creta.
(vi) The pair of sisters A and F travels in the same vehicle.
What is the profession of F?