Question

The distance traveled in a car varies directly as the amount of gasoline used. If a car travels 640 miles and uses 32 gallons of gas, determine the constant of proportionality (miles per gallon).

The constant of proportionality is ___
miles per gallon

Answer 1

To determine the constant of proportionality (miles per gallon), you can use the formula for direct variation:

\[
\text{Distance} = k \times \text{Gasoline used}
\]

where \( k \) is the constant of proportionality. Given that the car travels 640 miles and uses 32 gallons of gas, we can substitute these values into the equation:

\[
640 = k \times 32
\]

Next, we solve for \( k \):

\[
k = \frac{640}{32}
\]

Calculating this gives:

\[
k = 20
\]

Thus, the constant of proportionality is \( 20 \) miles per gallon.

So, the answer is:

The constant of proportionality is **20** miles per gallon.