(C) Let the distance to the destination be $d \text{ km}$.Speed of the boat in still water $= 10 \text{ km/h}$.Speed of the stream $= 4 \text{ km/h}$.

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(C) Let the distance to the destination be $d \text{ km}$.Speed of the boat in still water $= 10 \text{ km/h}$.Speed of the stream $= 4 \text{ km/h}$.Speed downstream $= 10 + 4 = 14 \text{ km/h}$.Speed upstream $= 10 - 4 = 6 \text{ km/h}$.The total time taken is the sum of time taken downstream and time taken upstream: $\frac{d}{14} + \frac{d}{6} = 5$.Taking the least common multiple of $14$ and $6$,which is $42$:$\frac{3d + 7d}{42} = 5$$\frac{10d}{42} = 5$$10d = 5 \times 42$$10d = 210$$d = 21 \text{ km}$.

Competitive Quantitative Aptitude Boats and Streams Boats and Streams

Medium

$A$ person takes total $5$ $hours$ to go to a destination downstream and come back upstream by boat. If the speed of the boat in still water is $10 \text{ km/h}$ and the speed of the stream is $4 \text{ km/h}$,what is the distance of the destination from the starting point (in $\text{km}$)?

A
$16$
B
$18$
C
$21$
D
$25$

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Boats and Streams

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Boats and Streams

The speed of a boat in still water is $7\, km/h$. If its speed in downstream is $10\, km/h$,then the speed of the stream is .......... $km/h$.

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If a boat goes upstream at a speed of $21\, km/h$ and comes back the same distance at $28\, km/h$,what is the average speed (in $km/h$) for the total journey?

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$A$ man can row at $10 \text{ km/h}$ in still water. If he takes a total of $5 \text{ h}$ to go to a place $24 \text{ km}$ away and return,then the speed of the water current is $... \text{ km/h}$.

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$A$ man takes $3$ $hours$ $45$ $minutes$ to row a boat $15 \; km$ downstream of a river and $2$ $hours$ $30$ $minutes$ to cover a distance of $5 \; km$ upstream. Find the speed of the river current in $km/hr$.

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In a stream running at $2 \, km/h$,a motorboat goes $10 \, km$ upstream and returns to the starting point in $55 \, min$. Find the speed of the motorboat in still water (in $km/h$).

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$A$ person takes total $5$ $hours$ to go to a destination downstream and come back upstream by boat. If the speed of the boat in still water is $10 \text{ km/h}$ and the speed of the stream is $4 \text{ km/h}$,what is the distance of the destination from the starting point (in $\text{km}$)?

Similar Questions

The speed of a boat in still water is $7\, km/h$. If its speed in downstream is $10\, km/h$,then the speed of the stream is .......... $km/h$.

If a boat goes upstream at a speed of $21\, km/h$ and comes back the same distance at $28\, km/h$,what is the average speed (in $km/h$) for the total journey?

$A$ man can row at $10 \text{ km/h}$ in still water. If he takes a total of $5 \text{ h}$ to go to a place $24 \text{ km}$ away and return,then the speed of the water current is $... \text{ km/h}$.

$A$ man takes $3$ $hours$ $45$ $minutes$ to row a boat $15 \; km$ downstream of a river and $2$ $hours$ $30$ $minutes$ to cover a distance of $5 \; km$ upstream. Find the speed of the river current in $km/hr$.

In a stream running at $2 \, km/h$,a motorboat goes $10 \, km$ upstream and returns to the starting point in $55 \, min$. Find the speed of the motorboat in still water (in $km/h$).

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