Two tuning forks a and b of frequency 200 hz and 200 hz are vibrated simultaneously. Then the ratio of time taken by the sound a and b to travel 660m and 490m respectively in air is ?
The ratio of time to travel 660 m : time to travel 490 m is 660:490.
Time = distance/velocity
The speed for sound from fork a is the same as for sound from fork b. So the time for sound from a to go 660 m will be longer than for sound from a to go 490 m by the ratio of the distances to be traveled. This would be true even if the frequencies were different.
I hope this helps,