A car $'A'$ chasing another car $'B'$ with a speed of $20\, m/s$ sounding a horn of $180\, Hz$. While both cars are moving towards a stationary siren of frequency $170\, Hz$. What is the speed of car $B$ so that it can't hear any beat ....$m/s$ (speed of sound $= 340\, m/s$)
  • A$34$
  • B$22$
  • C$20$
  • D$0$
Diffcult
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