Problem Statement
Seven people P, Q, R, S, T, U, V sit in a row facing north. Q is at an end. R is second to the right of Q. V is not at any end. T sits immediately left of V. U sits to the immediate right of P. Who is in the middle position?
Explanation
Place Q at an end. Case 1: Q at left end (pos1). Then R second to right ⇒ R at pos3. V is not at any end. T sits immediately left of V ⇒ T-V as a pair. U immediately right of P ⇒ P-U pair. Try filling: Positions so far _ Q R _ _ _ _. But we fixed Q at pos1; actually pos1=Q, pos3=R. Fit T-V somewhere consecutive not at ends (V can be pos5 with T pos4; or V pos6 with T pos5). Also P-U consecutive somewhere. After trials, a consistent fill is: Q R S T V P U, with V at pos5 (middle). Case 2: Q at right end mirrors to the same outcome with V central. Hence V is in the middle.
Code Solution
SolutionRead Only
One valid: Q R S T V P U ⇒ middle=V
Practice Sets
This question appears in the following practice sets:
