GATE Electrical Engineering (EE) 2018 Solved Paper

Question : 9 of 65

Marks: +1, -0

{P}, {Q}, {R}

and S crossed a lake in a boat that can hold a maximum of two persons, with only one set of oars. The following additional facts are available
i. The boat held two persons on each of the three forward trips across lake and one person on each of the two return trips.
ii. P is unable to row when someone else is in the boat.
iii.

Q

is unable to row with anyone else except

R

.
iv. Each person rowed for at least one trip.
v. Only one person can row during a trip. Who rowed twice?

Validate

Solution:

Since, P cannot row with anyone else so P must row while on return journey.
So, on first trip P & S leave in which S rows.
On the return trip P will row
On next trip P will leave with

R

and

R

will row &

P

will get down on other end. Now

R

will return & row to pick Q up.
On the last trip

Q

R will go in which

Q

will row the boat.
Hence, R rowed the boat twice

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