In such type of questions, clues are given regarding comparisons among a set of persons or things with respect to one or more qualities. The candidate is required to analyse the whole information, form a proper ascending / descending sequence and then answer the given questions accordingly.
A * B means A and B are of the same age;
A - B means B is younger than A;
A + B means A is younger than B;
Deven - Shashi * Hemant is opposite to
(i). Hemant + Shashi + Deven
(ii). Hemant - Shashi + Deven
(iii). Shashi * Hemant + Deven
Deven - Shashi * Hemant means Shashi is younger than Deven, and Shashi and Hemant are of the same age. Thus, Deven is the oldest. Now, the opposite statement would mean : Deven is the youngest.
(i). Hemant + Shashi + Deven means Hemant is younger than Shashi, who is younger then Deven. So, Deven is the oldest.
(ii). Hemant - Shashi + Deven means Shashi is younger than both Hemant and Deven. Thus, either Hemant or Deven is the oldest, but Deven is not the youngest.
(iii). Shashi * Hemant + Deven means Shashi and Hemant are of the same age and Hemant is younger than Deven. So, Deven is the oldest.