Let's assume that the price of crude oil is $37.00 per barrel. At 19.5 gallons of gasoline per barrel, this means that a gallon of gasoline in its crude oil form costs $1.90.
Johnny Tillotson is 77 years old (birthdate: April 20, 1939).
One more thing. Sometimes you will see people spell till as a contraction of until: that is, as 'til. This is simply wrong, and not seen outside of old poetry and modern greeting cards aiming for a poetic tone. Anywhere you see 'til being used, till would be the correct word.