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Boats & Streams, Pipes & Cisterns · Question 24 of 85

How long does the swimmer take to swim back upstream?

Question 24

EasyOriginal question

A swimmer swims at 4 km/h in still water. In a river flowing at 2 km/h, she swims 3 km downstream and then swims back to where she started.

How long does the swimmer take to swim back upstream?

30 minutesCorrect answerYour answer45 minutesCorrect answerYour answer60 minutesCorrect answerYour answer90 minutesCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer D

Correct answer: D

Upstream speed $= 4 - 2 = 2$ km/h.
$\frac{3}{2} = 1.5$ hours, 90 minutes.

Worth noting

30 minutes is the time downstream.

Concept: Speed upstream
Typical timeTypical: 90 s
Your timeYours: —

The rule this testsJourneys on a river

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