Task: Question Answering
Input (English): Problem: a certain car traveled twice as many miles from town a to town b as it did from town b to town c . from town a to town b , the car averaged 20 miles per gallon , and from town b to town c , the car averaged 25 miles per gallon . what is the average miles per gallon that the car achieved on its trip from town a through town b to town c ? 
Options: a ) 20 , b ) 18 , c ) 21.4 , d ) 16 , e ) 10
Output (English): c