Miscellaneous Question 16
- A man takes 2.2 times as long to row a distance upstream as to row the same distance downstream. If he can row $55$ $ km$ downstream in 2 hours 30 minutes, what is the speed of the boat in still water? (in $km / h$ )
(1) 40
(2) 8
(3) 16
(4) 24
(5) 32
(IBPS RRBs Officer Scale-I & II CWE 13.09.2015)
Show Answer
Correct Answer: 16. (3)
Solution:
- (3) Rate downstream $=\frac{55}{\frac{5}{2}}$
$=\frac{55 \times 2}{5}=22 $ $\mathrm{kmph}$
Time taken in upstream journey
$=\left(\frac{5}{2} \times 2.2\right)$ hours
$=5.5$ hours
$\therefore$ Rate upstream $=\frac{55}{5.5}$
$=10 $ $\mathrm{kmph}$
$\therefore$ Speed of boat in still water
$=\frac{1}{2}(22+10)$
$=\frac{1}{2} \times 32=16 $ $\mathrm{kmph}$
BETA
