Which ratio is equivalent to the unit rate 30 miles 1 gallon ? how was the unit rate transformed into the equivalent ratio? a) 3 gallons 10 miles ; by dividing the numerator and denominator of the unit rate by 10. b) 90 miles 5 gallons ; by multiplying the numerator and denominator of the unit rate by 3. eliminate c) 6 gallons 180 miles ; by multiplying the numerator and denominator of the unit rate by 2. d) 180 miles 6 gallons ; by multiplying the numerator and denominator of the unit rate by 6.