At a corner gas station, the revenue R varies directly with the number g of gallons of gasoline sold. If the revenue is $56.40 when the number of gallons sold is 12, find a linear equation that relates revenue R to the number g of gallons of gasoline. Then find the revenue R when the number of gallons of gasoline sold is 7.5.

(i) R = 4.70g

(ii) R = $35.25

Step-by-step explanation:

(i) R ∞ g

Removing the proportionality symbol, we have

R = kg, where k is the constant of proportion

56.40 = k(12)

Divide both sides by 12

56.40/12 = k(12)/12

$4.70 = k

k = $4.70

So, R = 4.70g (which is the linear equation relating Revenue, R to number of gallons, g)

(ii) When g = 7.5,

R = 4.70 * 7.5 = 35.25

R = $35.25