17.

Question

The total cost of gasoline varies directly with the number of gallons purchased. Gas costs $1.89 per gallon. Write a direct variation to model the total cost c for g gallons of gas.

Answer 1

To model the total cost \( c \) for \( g \) gallons of gas that costs $1.89 per gallon, we can use the formula for direct variation:

\[ c = kg \]

where \( k \) is the constant of variation (the cost per gallon in this case). Given that gasoline costs $1.89 per gallon, we can substitute \( k \) with \( 1.89 \):

\[ c = 1.89g \]

Thus, the direct variation that models the total cost \( c \) for \( g \) gallons of gas is:

\[ c = 1.89g \]