You should start with an equation.
The 'x' represents the week.
so now, we have to subtract 125 from the total amount which is 245.
now we have
to find 'x', we must divide 15 on each side
we are now left with
that means Sierra will have 8 weeks until she has enough money to buy the bike
18.84 I think you have to do the math from the radius to the edge of the circle
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.