Answer:
Andy went as furthest as possible with a gallon of gasoline
Explanation:
Let
m ----> the distance in miles
g ----> the number of gallons of gas
step 1
Kelley's Mileage
Find the slope of the linear function of Kelley's Mileage
we have the points
(0,0) and (20,50)
![slope=(50-0)/(20-0)\\slope=2.5\ miles/gallon](https://img.qammunity.org/2020/formulas/mathematics/middle-school/agys8l5gv2rmhas4znbxxw95h4npyz56s2.png)
the linear equation is
![m=2.5g](https://img.qammunity.org/2020/formulas/mathematics/middle-school/lkznacmgyepufpmg52r6a9b7haaljwwb5d.png)
step 2
Andy's Mileage
Find the slope of the linear function of Andy's Mileage
we have the points
(15,78.75) and (30,157.5)
![slope=(157.5-78.75)/(30-15)\\slope=5.25\ miles/gallon](https://img.qammunity.org/2020/formulas/mathematics/middle-school/i44e6p0lkt1uib8b00z53ltdsde2q3okt6.png)
the linear equation is
![m=5.25g](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xje0orccrd8v7ypq8vsiu4si4erdyo25ml.png)
step 3
Rick's Mileage
we have
![m=4.8g](https://img.qammunity.org/2020/formulas/mathematics/middle-school/3g97s8rjj6ddh77mby1d1tw9plbg8ccfmg.png)
therefore
the slope is
![4.8\ miles/gallon](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5u7oy5kfp6w8jd9puqtm1ahhtti0ns0buf.png)
step 4
Compare the slopes
![5.25\ miles/gallon > 4.8\ miles/gallon > 2.5\ miles/gallon](https://img.qammunity.org/2020/formulas/mathematics/middle-school/co9boct4cjc6vh1jzufoc34z1eje1srbmo.png)
therefore
Andy went as furthest as possible with a gallon of gasoline