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

M4maths Previous Puzzles

24 Feb 2010 Whistle speed in wind?

Ram 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 Ram. If Ram 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) 60
(6) 90
(7) Wind is not blowing
(8) Data are insufficient
(9) 70
(10) 20

Solution

Ram 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 Ram. These data indicate that wind is blowing from Shyam to Ram
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

Correct Option: 5 Best Solution (4)

Dr.Dipin Singh   14 years AGO

If D is distance between the, s is speed of sound and w is speed of wind, then.........

D/( s+w) = 2 and D/(s-w) = 3
hence D= 2*( s+w)= 3*(s-w) ... s= 5w

Hence speed of wind =s/5 = 300/5= 60 m/sec..option 5

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Dimple   14 years AGO

Distance between Ram and Shyam = 2*( speed of sound + speed of wind) = 3*( speed of sound - speed of wind)

solving this , we get ,

speed/velocity of wind = Speed of sound/5= 300/5 = 60 m/sec

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HARMEET KAUR   14 years AGO

Time taken to travel same distance in direction of wind with speed ( sound + wind ) = 2 secs
Time taken to travel same distance in opposite direction of wind with speed ( sound - wind ) = 3 secs

solving this, we get , speed of sound is 5 times speed of sound i.e. 300/5=60 m/sec

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Saravanan   14 years AGO

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

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