Find the missing number from the below options.
| 19 | 78 | 20 |
| 25 | 144 | 47 |
| 16 | ? | 13 |
Observe that the middle entry equals \(2 \times (\text{left} + \text{right})\):
Row 1: \(2 \times (19 + 20) = 2 \times 39 = 78\) → matches.
Row 2: \(2 \times (25 + 47) = 2 \times 72 = 144\) → matches.
Therefore, Row 3: middle \(= 2 \times (16 + 13) = 2 \times 29 = 58\).
\(\boxed{58}\)
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?