Eleven students A, B, C, D, E, F, G, H, I J and K are sitting in the first row of the class facing the teacher.<br /> D who is the immediate left of F is second to the right of C.<br /> A is second to the right of E, who is at one of the ends.<br /> J is the immediate neighbour of A and B and third to the left of G.<br /> H is to the immediate left of D and third to the right of I.<br /> If E and D, C and B, A and H and K and F interchange their positions, which of the following pairs of students are sitting at the ends?
Step-by-step Solution:
$$ \textbf{Original\ row\ (positions\ 1\ to\ 11):} \qquad \begin{aligned} 1 &: E\\ 2 &: K\\ 3 &: A\\ 4 &: J\\ 5 &: B\\ 6 &: I\\ 7 &: G\\ 8 &: C\\ 9 &: H\\ 10 &: D\\ 11 &: F \end{aligned} $$ Perform the interchanges: $$ \textbf{After\ interchanges:} \qquad \begin{aligned} 1 &: D\\ 2 &: F\\ 3 &: H\\ 4 &: J\\ 5 &: C\\ 6 &: I\\ 7 &: G\\ 8 &: B\\ 9 &: A\\ 10 &: E\\ 11 &: K \end{aligned} $$