If f(x) and f^-1(X) are inverse functions of each other and f(x)=2x+5, what I f^-1(8)
1 answer:
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Answer:
B
Step-by-step explanation:
For 11 1/2 gallons, he paid $36.80.
We need to find the cost per gallon.
First, converting 11 1/2 gallons to decimal, it is:
1/2 = 0.5
So, 11 1/2 is 11.5 gallons
So, Cost Per Gallon (last week) =
There is 5% increase on this $3.20 per gallon. We find 5% of 3.2 and add it to 3.2 to find this week's cost per gallon.
<em>5% = 5/100 = 0.05</em>
<em>0.05 * 3.20 = 0.16</em>
<em>So,</em>
<em>3.20 + 0.16 = $3.36 per gallon</em>
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Cost Per Gallon (this week) = $3.36
To buy 9 1/4 gallons it would take:
<u>Note:</u> 1/4 = 0.25, so 9 1/4 = 9.25
It would cost $31.08 to buy 9.25 gallons this week
Correct answer is B