Between which two cities among the pairs of cities given below are there maximum travel options available ?
aQ and S
bP and R
cP and T
dQ and R
AnswerUPSC’s answer is (a).
Count the routes without repeating a city, multiplying the mode choices on each leg. Q to S: via P is 2 (Q-P) x 1 (P-R) x 2 (R-S) = 4, and via T is 1 (Q-T) x 2 (T-R) x 2 (R-S) = 4, so 8 in all. P to R: the direct boat is 1, plus P-Q-T-R at 2 x 1 x 2 = 4, so 5. P to T: via R is 1 x 2 = 2 and via Q is 2 x 1 = 2, so 4. Q to R: via P is 2 and via T is 2, so 4. Q and S have the most options.
Why each option is right or wrong
(a) Right. 8 routes, 4 through P and 4 through T.
(b) Wrong. P and R have 5 routes.
(c) Wrong. P and T have 4 routes.
(d) Wrong. Q and R have 4 routes.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
