Answer:

And if we use the permutation formula given by:

And replacing we got:

Step-by-step explanation:
For this problem we want to find the following expressionÑ

And if we use the permutation formula given by:

And replacing we got:

So P stands for principle which is the amount of the original investment, R stands for rate which is the percent but must be turned into a decimal, T stands for time for example if the time was in a certain amount of months then you plug that in with x/12, and lastly I stands for interest which is the original investment outcome ^_^
Answer:
A) R = 1900 -24t
B) 1684 billion barrels
C) 79.17 years
Step-by-step explanation:
<h3>A)</h3>
Reserves start at 1900 billion barrels and decrease by 24 billion barrels each year. The value for t=0 is 1900; the value for t=1 is 24 less.
R = 1900 -24t
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<h3>B)</h3>
For t=9, the reserves will be ...
R = 1900 -24(9) = 1900 -216 = 1684 . . . . billion barrels
__
<h3>C)</h3>
The reserve will be 0 when ...
0 = 1900 -24t
24t = 1900 . . . . . add 24t
t ≈ 79.17 . . . . divide by 24
Reserves will be gone in about 79.17 years.