Chapter 3 - 3.5 - Mathematical Modeling and Variation - 3.5 Exercises - Page 296: 64

Mathematical model: $y=3.786x$ If $x=5~gallons$ $y=18.93~liters$ If $x=25~gallons$ $y=95.65~liters$

$y=kx$ When $y=53~liters$, $x=14~gallons$: $53=k(14)$ $k=\frac{53}{14}\approx3.786$ Then: $y=3.786x$ If $x=5~gallons$ $y=3.786\times5=18.93~liters$ If $x=25~gallons$ $y=3.786\times25=95.65~liters$