Ramesh hears a sound of whistle after 2 sec. of whistling by Shyam and Shyam hears a sound of whistl

M4maths Previous Puzzles

26 Nov 2014 Speed and Time

Ramesh hears a sound of whistle after 2 sec. of whistling by Shyam and Shyam hears a sound of whistle after 3 sec. of whistling by Ramesh. If Ramesh and Shyam are in the line of flow of wind, then velocity of wind in m/s is
(Given that the speed of sound is 300 m/s)

OPtion

1) 80
2) 50
3) 40
4) 30
5) 70
6) 90
7) Wind is not blowing
8) Data are insufficient
9) 60
10)20

Solution

Ramesh hears a sound of whistle after 2 sec. of whistling by Shyam and Shyam hears a sound of whistle after 3 sec.
(greater than 2 sec.) of whistling by Ramesh. These data indicate that wind is blowing from Shyam to Ramesh
According to first condition l = (300 + x) 2,
l represents distance between them
According to second condition l = (300 - x) 3
On solving these equations, we get x = 60

Option 9)

Correct Option: 9 Best Solution (29)

RAKESH   10 years AGO

velocity of wind = x m/s then
equate distance b/w Ramesh & Shyam

(300+x)*2 = (300-x)*3
=> x = 60

Like? Yes (6) | No (4)  

Pramod Gaikwad   10 years AGO

consider speed of wind x m/s
distance between shyam and ramesh is same,
so v=distance /time.
distance=(300+x)*2
and
distance =(300-X)*3
by solving this we get
x=60
i.e. option 9)60.

Like? Yes (3) | No (2)  

khushboo goenka   10 years AGO

dis between ramesh and shyam is 300-w/2=150
simi;arly, 300+w/3
both are eql
so w=60

Like? Yes (1) | No   

Deepak prajapati   10 years AGO

(300+v)*2=(300-v)*3
v=60

Like? Yes (2) | No (1)  

K.ARun   10 years AGO

Ramesh hears sound after 2secs. of whistling by shyam so 2(300+x)
Shyam hears after 3secs. of whistling by Ramesh
so 3(300-x)
Note: (-x) due to line of flow of wind
so 2(300+x)=3(300-x)
600+2x=900-3x
5x=300;
x=60

Like? Yes (3) | No (3)  

ANIL KUMAR   10 years AGO

let the speed of air =x m/s
so , the equation formed is:

(300+x)2=(300-x)3
600+2x=900-3x
5x=300
x=60

Like? Yes (1) | No (1)  

PAWAN KUMAR   10 years AGO

Let the speed of wind be t m/s and distance between them be x mtr.
Then, x/(300+t) = 2 ------------(i)

and x/(300-t) = 3------------(ii)
on solving (i) and (ii), we get;
600+2t = 900-3t
=> t = 60 m/s Ans.

Like? Yes (1) | No (1)  

Pinaki Ghosh   10 years AGO

((300 * 3) - (300*2)) / (2+3) = 60

Like? Yes (1) | No (1)  

Ranjit Somisetty   10 years AGO

v=d/t => d=v*t Here d is constant.
(300+v)2=(300-v)3
v=60m/s, velocity of wind.

Like? Yes (1) | No (1)  

sravani   10 years AGO

the distance between them is same..so v1t1=v2t2
v1 be the velocity of sound+wind at ramesh side
v2 at shyam side
as shyam takes more time to listen he is opposite to wind blow...
so
2*(300+x)=3*(300-x) (let X is the speed of wind)
x=60..

Like? Yes (1) | No (1)  

Sagar Kharab   10 years AGO

2(300+v)=3(300-v)
600+2v=900-3v
5v=300
V=60

Like? Yes (1) | No (1)  

Swagatam Kumar Das   10 years AGO

Let the speed of wind is u
So 2(300+u)=3(300-u)
So u=60

Like? Yes (1) | No (1)  

kanchapu ramanjan   10 years AGO

(300-60)*3=(300+60)*2

Like? Yes (1) | No (1)  

prem kumar chaudhary   10 years AGO

v(w)=velocity of wind
2(300+v(w))=(300-v(w))3
v(w)=60
ans=60

Like? Yes (1) | No (1)  

vaitesh mudaliar   10 years AGO

let the direction of wind be from shyam to ramesh and has speed =s.
when shyam blows whistle, speed of sound traveled will be = wind speed + actual speed of sound
dist traveled (d) = speed of sound travelled * time
d= (s+300)*2
when ramesh blows whistle,
d= (300-s) *3
equating both eqn.
we get s= 60 m/s

Like? Yes (1) | No (1)  

sanjeev kumar   10 years AGO

ans 60

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Divyen Jain   10 years AGO

(300+Vs)2 = d = (300-Vs)3
Vs= 60

Like? Yes (1) | No (1)  

CHANDAN KUMAR   10 years AGO

speed of sound=s
speed of wind=w
2(s+w)=3(s-w)
2(300+w)=3(300-w)
5w=300
w=300/5=60m/s

Like? Yes (1) | No (1)  

Dipu Kumar   10 years AGO

since ramesh takes less time to hear whistal it means direction of blow of wind is shayam to ramesh.
Let x is velocity of wind.
distace cover by whistal from shyam to ramesh=2*(300+x)
''' '' '' '' '' ' '''' ''' '' ramesh to shyam=3*(300-x)
both distance are equal
2*(300+x)=3*(300-x)
x=60 m/s

Like? Yes (1) | No (1)  

RAJESH   10 years AGO

60

Like? Yes (1) | No (1)  

SUBHASH TULSYAN   10 years AGO

let the distance b/w them is k
let the speed of wind is x
a/q
we hv the following eqn
k/(300+v)=2............(1)
k/(300-v)=3...........(2)
from (1) & (2)
2(300+v)=3(300-v)
on solving
x=60

Like? Yes (2) | No (2)  

akhil sai   10 years AGO

from v=d/t
both are separated by same distance but wind is in one direction so (v+x)=d/2
(v-x)=d/3 where v=300m/s velocity of sound x=wind velocity
same direction less time opposite direction more time

Like? Yes (2) | No (2)  

Ramesh sai   10 years AGO

300/2+3=60m/s

Like? Yes (1) | No (1)  

Sourabh Prasad   10 years AGO

60 m/s

Like? Yes (1) | No (1)  

sriharidatta   10 years AGO

300/ (3+2)

Like? Yes (1) | No (1)  

ravi prakash   10 years AGO

let speed of wind=x m/sec
then (300+x)2=(300-x)3
x=300/5
60

Like? Yes (1) | No (2)  

Md.Sultan Khichi   10 years AGO

Let the velocity of wind be x m/s.
So (x+300)/2=(300-x)/3
After solving x=-60
-ve sign indicate that wind blowing in opposite direction..
So speed of wind is 60 m/s.
Ans. Ob 9

Like? Yes (1) | No (2)  

Rajat Rokade   10 years AGO

Suppose, the speed of wind is X m/s.
Now the distance between Ramesh and Shyam is same.
so,
the ratio of the time must be equal to the relative speed of wind.

(300 + X)/(300 - X) = 3/2.
Solving this equation, we get X=60.
Speed of wind is 60 m/s.

Like? Yes (3) | No (4)  

Rahul Rathod   10 years AGO

let velocity of wind=x;
dist(Ramesh)=dist(Shyam)
so
(300+x)/(300-x)=3/2
so x=60
answer is 60

Like? Yes (2) | No (3)