Answer:
$36.41/week
Step-by-step explanation:
Divide 750 miles/wk by 28 MPG -> = 26.79 gallons/week (I rounded.)
Divide 750 miles/wk by 20 MPG -> = 37.50 gallons/week
Car -> 26.79 gallons x $3.40 = $91.09
SUV -> 37.50 gallons x $3.40 = $127.50
$127.50 - $91.09 = Difference of $36.41/week