A) 5 min
B) 60 min
C) 20 min
D) 30 min
Correct Answer: D
Solution :
Time taken by the boat to reach the other side is \[Time=\frac{distance}{relative\text{ }speed}\] Relative speed\[=\sqrt{{{5}^{2}}-{{3}^{2}}}=\sqrt{16}=4\,km/h\] \[\therefore \] \[T=\frac{1\,km}{4\,km/h}=0.25\,h\] To come back boat takes the same time, hence total time is \[T=2\times 0.25=0.5\text{ }h\] Also, 1 h = 60 min 0.5 h = 30 minYou need to login to perform this action.
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