Question 229950
The amount of time it takes a swimmer to swim a race is inversely proportional to the average speed of the swimmer. 
time = k[1/s]
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If a swimmer finishes a race in 37.5 seconds having an average speed of 4ft./sec. 
Use that information to find "k":
37.5 = k[1/4]
k = 150
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Now you know the equation for your problem is
time = 150[1/s]
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Find the average speed of a swimmer if it takes 30 seconds to finish the race. 
30 = 150[1/s]
1/s = 1/5
speed = 5 ft/sec
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Cheers,
stan H.