You fill your car with 15 gallons of gas at a cost of $45. Using fractional notation, how do you write a proportion that shows how much 5 gallons of gas will cost? Use x to represent the unknown cost.(1 point)

Question

Responses

15:45::x:5
ratio of 15 to 45 colon colon ratio of x to 5

15x=455
Start Fraction 15 over x End Fraction equals Start Fraction 45 over 5 End Fraction

1545=5x
Start Fraction 15 over 45 End Fraction equals Start Fraction 5 over x End Fraction

1545=x5

Answer 1

To write a proportion that shows how much 5 gallons of gas will cost using \( x \) to represent the unknown cost, the correct setup is:

\[ \frac{15}{45} = \frac{5}{x} \]

This means the ratio of 15 gallons to the cost of $45 is equivalent to the ratio of 5 gallons to the unknown cost \( x \).

Among the options given, the equivalent expression is:

Start Fraction 15 over 45 End Fraction equals Start Fraction 5 over x End Fraction

Thus, the proportion would be:

\[ \frac{15}{45} = \frac{5}{x} \]