Miscellaneous Question 37
- A boat can travel $6.4 $ $km$ downstream in 16 minutes and $9.9$ $ km$ upstream in 33 minutes. What is the total time taken by the boat to travel $48 $ $km$ upstream and the same distance downstream together?
(1) $4$ hrs $40$ min
(2) 4 hrs
(3) $5$ hrs
(4) $5$ hrs $20$ min
(5) $5$ hrs $40$ min
(IBPS RRBs Officer CWE (Prelim Exam) 16.09.2017)
Show Answer
Correct Answer: 37. (5)
Solution: 37. (5) Rate downstream of boat
$=\left(\frac{6.4}{\frac{16}{60}}\right) $ $\mathrm{kmph}$.
$=\left(\frac{6.4 \times 60}{16}\right)$ $ \mathrm{kmph}$.
$=24 $ $\mathrm{kmph}$.
Rate upstream of boat
$=\left(\frac{9.9}{\frac{33}{60}}\right)$ $ \mathrm{kmph}$.
$=\left(\frac{9.9 \times 60}{33}\right) $ $\mathrm{kmph}$.
$=18 $ $\mathrm{kmph}$.
$\therefore$ Required time
$=\left(\frac{48}{24}+\frac{48}{18}\right)$ hours
$=\left(3+\frac{8}{3}\right)$ hours
$=5$ hours $\frac{2}{3} \times 60$ minutes
$=5$ hours 40 minutes
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