Answers:
Exponential decay model is y = 500*0.88^x
There is roughly 0.0000000000237 mL of the original air left.
There are 10 zeros between the decimal point and the '2'
The number in scientific notation is
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Further Explanation:
A general exponential equation is
y = a*b^x
We start with 500 mL of air which is the value of 'a'
If 12% of the air is replaced, then 88% of it remains because 12% + 88% = 100%
Convert 88% to the decimal form 0.88 and this represents the base of the exponent. This is the value of b.
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Since a = 500 and b = 0.88, we have
y = a*b^x
y = 500*0.88^x
Now we plug in x = 240 to estimate how much of the original air is in the lungs after that many breaths.
y = 500*0.88^x
y = 500*0.88^240
y = 0.0000000000237
This number is very small and to be expected since quite a bit of breaths have occurred. Nearly all of the original air particles should be replaced by this point. A very small trace amount remains.
Notes:
- There are 10 zeros between the decimal point and the '2' in the number 0.0000000000237
- The number 0.0000000000237 is so small that it probably makes sense to use scientific notation to write
meaning we move the decimal point 11 spots to the left to go from 2.37 back to 0.0000000000237 - The number 0.0000000000237 is read out as "237 ten-trillionths". Imagine splitting an object into ten trillion tiny pieces, and then shading 237 of those pieces to represent this decimal number.