<PRE><B>Question 635715</B>
A bullet is fired at a target and the sound its impact is heard 6 seconds later.
 If it travels at the rate of 2200 feet per second and sound travels at the rate
 of 1100 feet per second, how far away is the target?
:
Let d = distance to the target
:
Write a time equation: time = dist/speed
:
bullet time + impact sound time = 6 seconds
{{{d/2200}}} + {{{d/1100}}} = 6
multiply by 2200
2200*{{{d/2200}}} + 2200*{{{d/1100}}} = 2200*6
cancel out denominators, and you have
d + 2d = 13200
3d = 13200
d = 13200/3
d = 4400 ft to the target
:
:
confirm this, find the time each way
4400/2200 = 2 sec
4400/1100 = 4 sec
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total time: 6 sec </PRE>