Miscellaneous Question 38
- The time taken by a boat to travel $(D+12)$ km upstream is double of that taken to travel ’ $D$ ’ $km$ downstream. If the respective ratio between the speed of boat in still water and the speed of the current is $5: 1$, what is the value of $D$ ?
(1) 24
(2) 36
(3) 25
(4) 30
(5) 38
(IBPS Bank PO/MT CWE-VII (Prelim Exam) 14.10.2017)
Show Answer
Correct Answer: 38. (2)
Solution: 38. (2) Speed of boat in still water $=5 x $ $\mathrm{kmph}$
Speed of current $=x$ $ \mathrm{kmph}$.
$\therefore$ Rate downstream $=6 x $ $\mathrm{kmph}$.
Rate upstream $=4 x $ $\mathrm{kmph}$
According to the question,
$\frac{\mathrm{D}+12}{4 x}=\frac{2 \mathrm{D}}{6 x}$
$\Rightarrow \frac{\mathrm{D}+12}{2}=\frac{2 \mathrm{D}}{3}$
$\Rightarrow 4 \mathrm{D}=3 \mathrm{D}+36$
$\Rightarrow \mathrm{D}=36$ $ \mathrm{km}$.
BETA
