Two trains move towards each other with the same speed. The speed of sound is $340 \;m / s$. If the height of the tone of the whistle of one of them heard on the other changes $9 / 8$ times, then the speed of each train should be ........... $m/sec$
  • A$20$
  • B$2$
  • C$200$
  • D$2000$
AIPMT 1991, Medium
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