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The function [tex]f(x)=\frac{2.14}{55} x+0.31[/tex] can be used to determine the cost of a gallon of gas [tex]x[/tex] years since 1960. According to the function, what was the cost of a gallon of gas in 1960, and approximately how much did the cost increase each year?

Select and drag numbers to the empty boxes to complete the sentences correctly.

1. In 1960, gas cost [tex]$\_\_\_$[/tex] per gallon.
2. Since 1960, the cost of gas increased at a constant rate of approximately [tex]$\_\_\_$[/tex] per gallon.

Options:
- [tex]$\$[/tex] 0.04[tex]$
- $[/tex]\[tex]$ 25.70$[/tex]
- [tex]$\$[/tex] 0.40[tex]$
- $[/tex]\[tex]$ 0.31$[/tex]
- [tex]$\$[/tex] 0.39[tex]$
- $[/tex]\[tex]$ 2.61$[/tex]
- [tex]$\$[/tex] 2.14$



Answer :

To determine the cost of a gallon of gas in 1960 and the rate of increase per year using the function [tex]\( f(x) = \frac{2.14}{55}x + 0.31 \)[/tex]:

1. Cost of Gas in 1960:
To find the cost of a gallon of gas in 1960, we look at [tex]\( f(x) \)[/tex] when [tex]\( x = 0 \)[/tex]. Plugging [tex]\( x = 0 \)[/tex] into the function:
[tex]\[ f(0) = \frac{2.14}{55} \cdot 0 + 0.31 = 0.31 \][/tex]
Therefore, in 1960, gas cost [tex]\(\$0.31\)[/tex] per gallon.

2. Rate of Increase per Year:
The rate of increase per year is represented by the coefficient of [tex]\( x \)[/tex] in the function. This coefficient is:
[tex]\[ \frac{2.14}{55} \approx 0.0389 \][/tex]
When rounded to the nearest cent, this translates to [tex]\(\$0.04\)[/tex] per gallon each year.

Therefore:
- In 1960, gas cost [tex]\(\$0.31\)[/tex] per gallon.
- Since 1960, the cost of gas increased at a constant rate of approximately [tex]\(\$0.04\)[/tex] per gallon.