Answer: the price of purchasing 20 gallons is $32.96
Step-by-step explanation:
If two variables are directly proportional, it means that an increase in the value of one variable would cause a corresponding increase in the other variable. Also, a decrease in the value of one variable would cause a corresponding decrease in the other variable.
Let x represent the number of gallons purchased, and let y represent the total price.
Given that y varies directly with x, if we introduce a constant of proportionality, k, the expression becomes
y = kx
If y = $37.9 when x = 23 gallons, then
37.9 = 23k
k = 37.9/23
Therefore, the direct variation equation is
y = 37.9x/23
When x = 20 gallons, then
y = 37.9 × 20/23
y = $32.96