Question

Yesterday, I put 10 gallons of gas in my car and I paid $30. A couple hours

after, I went back to the gas station with my dad's car and after filling up the
tank, I paid $18. How many gallons of gas did I put in my dad's car?

Answer 1

6 gallons

Explanation:

1) $30/10 gallons= $3 per gallon

So...

2) $18/3=6 gallons