The fuel efficiency for a new helicopter engine is given by the continuous function r(c) where r is measured in gallons per mile

The question is incomplete. The complete question is :

The fuel efficiency for a new helicopter engine is given by the continuous function r(c) where r is measured in gallons per mile and c is measured in miles. What are the units of   ?

Solution :

The given continuous function is :

r(c), here c is measured in miles and the unit of r is measured in gallons per mile.

So the unit of   is given by :

= gallons per mile x mile

= gallons

So, the final unit is gallons.