Miscellaneous Question 34
- A boat can travel $9.6 $ $km$ downstream in 36 minutes. If speed of the water current is $10 \%$ of the speed of the boat in downstream, how much time will boat take to travel $19.2$ $ km$ upstream?
(1) 2 hours
(2) 3 hours
(3) 1.25 hours
(4) 1.5 hours
(5) 1 hour
(IBPS RRBs Officers CWE (Prelim Exam) 09.09.2017 IInd Sitting)
Show Answer
Correct Answer: 34. (4)
Solution: 34. (4) Rate downstream of boat
$=\left(\frac{9.6}{\frac{36}{60}}\right) $ $\mathrm{kmph}$.
$=\left(\frac{9.6 \times 60}{36}\right) $ $\mathrm{kmph}$.
$=16 $ $\mathrm{kmph}$.
Speed of current $=1.6$ $ \mathrm{kmph}$.
$\therefore$ Speed of boat in still water
$=(16-1.6) $ $\mathrm{kmph}$.
$=14.4 $ $\mathrm{kmph}$.
$\therefore$ Rate upstream of boat
$=(14.4-1.6)$ $ \mathrm{kmph}$.
$=12.8 $ $\mathrm{kmph}$.
$\therefore$ Required time
$=\left(\frac{19.2}{12.8}\right)$ hours
$=1.5$ hours
BETA
