SOLUTION: Light intensity is reduced by 3.5% for each meter a diver descends below the water surface. At what depth is the light intensity only 15% of that at the surface?

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Question 1114123: Light intensity is reduced by 3.5% for each meter a diver descends below the water surface. At what depth is the light intensity only 15% of that at the surface?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Light intensity is reduced by 3.5% for each meter a diver descends below the water surface.
At what depth is the light intensity only 15% of that at the surface?
:
a 3.5% reduction = 96.5% of the light remains
using the decimal equiv of per cent
d = depth in meters
1%2A.965%5Ed+=+.15
using natural logs
ln%28.965%5Ed%29 = ln%28.15%29
the log equiv of exponent
d%2Aln%28.965%29 = ln%28.15%29
d = ln%28.15%29%2Fln%28.965%29
d = 53.25 meters below the surface