Task: Question Answering
Input (English): Problem: a runs twice as fast as b and gives b a start of 42 m . how long should the racecourse be so that a and b might reach in the same time ? 
Options: a ) 75 m . , b ) 80 m . , c ) 84 m . , d ) 100 m . , e ) none of the above
Output (English): c