Seja E a expressão que queremos calcular:
1/100,000,000 , note that 100,000,000 = 10⁸ , then:
1/100,000,000 = 1/10⁸
Remember that 1/aⁿ = a⁻ⁿ
Hence 1/100,000,000 = 1/10⁸ = 10⁻⁸
To solve this we are going to use the half life equation

Where:

is the initial sample

is the time in years

is the half life of the substance

is the remainder quantity after

years
From the problem we know that:



Lets replace those values in our equation to find

:




We can conclude that after 1600 years of radioactive decay, the mass of the 100-gram sample will be
91.7 grams.
Well 33 is rounded down to 30
And 89 is rounded up to 90
So it would be 120
Anything from 1-4 is rounded down and anything 5-9 is rounded up
Step-by-step explanation:
The total bill will be the sum of the rent and the cost for the total time spent.
$15 + $6 * 2.5
$15 + $15
$30