SOLUTION: Please help me solve this problem: A glass 1 cm thick allows only 80% of the light to filter through. How much light will filter through a glass 2 cm thick?

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Question 876989: Please help me solve this problem:
A glass 1 cm thick allows only 80% of the light to filter through. How much light will filter through a glass 2 cm thick?
Found 2 solutions by jim_thompson5910, KMST:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
80% of 80% = 0.8*0.8 = 0.64 = 64%

So a 2 cm thick glass will let in 64% of the light.

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
The first 1-cm of glass thickness allows 80%2F100=8%2F5=0.8 of the light to filter through.
The next 1-cm of glass thickness allows 80%2F100=8%2F5=0.8 of the remaining light to filter through.
The fraction that filter through the 2-cm thickness is
%284%2F5%29%284%2F5%29=%284%2F5%29%5E2=16%2F25=64%2F100=0.64 .
So 64% of the light will filter through.

If it is a solution of an unchanging chemical species, the concentration of that substance plays the same role as d
Analytical chemists (like me) use that for chemical analysis.