Formula: Cost of Gas = (Distance in miles) / (Fuel Economy in mpg) * (Price of Gas per gallon)
Plugging in the values:
Cost of Gas = (160 miles) / (25 mpg) * ($3.50/gallon)
= 6.4 gallons * $3.50
= $22.40
Therefore, it would cost approximately $22.40 to drive 160 miles in a car with a 25 mpg fuel economy and a gas price of $3.50 per gallon.