A speedboat (18 km/h in still water) leaves ghat A at 9 a.m. for ghat B, 45 km upstream; the current is 3 km/h. At 9 a.m. a raft starts drifting down from B. The boat halts 30 minutes at B and then heads back. At what time does the boat catch up with the raft?

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Accepted Answer

1:05 p.m.. Boat reaches B at 12 noon (45 ÷ 15) and leaves at 12:30. The raft has drifted 3 × 3.5 = 10.5 km from B. Boat chases at 21 km/h, raft at 3 ⇒ 10.5 ÷ 18 = 35 min ⇒ 1:05 p.m. (11:30 a.m. is when they first pass each other.)

A speedboat (18 km/h in still water) leaves ghat A at 9 a.m. for ghat B, 45 km upstream; the current is 3 km/h. At 9 a.m. a raft starts drifting down from B. The boat halts 30 minutes at B and then heads back. At what time does the boat catch up with the raft?

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