M4maths Previous Puzzles

29 Aug 2019 Boats and Streams

A man goes down stream with a boat to some destination and returns upstream to his original place in 6 hours. If the speed of the boat in still water and downstream are 6km/hr and 8km/hr respectively, the distance of the destination from the starting place in KMs is

OPtion

1) 18
2) 15
3) 20
4) 19
5) 17
6) 16
7) 14
8) 13
9) 12
10) None of these

Solution

Let the distance be D

Speed of boat in still water = 6
Speed of boat in downstream = 8
Speed of Stream = 8- 6 = 2
Speed of boat in upstream = 6-2 = 4

Time Downstream + Time upstream = 6
=> D/8 + D/4 = 6
=> D = 16
Option 6)

Correct Option: 6 Best Solution (6)

G.S.Kantharao   5 years AGO

Relative speeds = 8,(6-2)
Distance=d
d/8+d/4=3d/8=6h
x=6*8/3=16km
My option is 6👈

Like? Yes (2) | No   

sonveer yadav   5 years AGO

Let 'D' be the distance.
speed of current = 8-6=2 km/hr.
time taken = 6 hours
D/4 + D/8 = 6
3D/8 = 6
D = 16 km

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Yashvanth   5 years AGO

d/X+y + d/x-y =6 hrs given
also given X=6 and DS =8 ,X+y =8 so y=2
substitute in top most equation we get
d= 16 kms

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Elizabeth Pothen   5 years AGO

Velocity of stream = 8-6 = 2 kmph
Upstream velocity of boat = 6- 2 = 4kmph
So t1 = d/8 and t2= d/4
Given t1+t2 6 hrs
So d/8 + d/4 = 6
Solving d = 16 km

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suryanarayana   5 years AGO

t=6hr
y=6kmph
u=8kmph
x=2kmph
v=4kmph
d/8+d/4=6
d=16

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Arkaprava Dutta   5 years AGO

Speed of boat=B=6 km/h,
Speed of stream=s.
Downstream speed=B+s=8km/h,
s=2km/h.
Therefore upstream speed=B-s= 6-2=4km/h.

Man goes with 8km/h, &
returns with 4km/h.
His average speed=(8*4) /(8+4) km/h
= 8/3 km/h.

His journey completed in 6hrs.
So the distance= (8/3)*6
= 16km/h

Like? Yes | No (1)