Question

if each foot of water in a lake screens out 60% of the light above, what percent of the light passes through 5 feet of water?

Answer 1

i think its a lot less than 40%
at 1 foot deep 40% of the light is left so at 2 ft another 60 % is filtered out which = 24% leaving only 16%.
Continuing this calculation there won't be much left at 5 ft.

Answer 2

to calculate the light passing thru 5 feet we have the formula
(0.4)^5 = 0.01024 or 1.024 %

Answer 3

my choices are 15% ,1.024% , 3.725%