Task: Question Answering
Input (English): Problem: a type r machine can complete a job in 5 hours and a type b machine can complete the job in 7 hours . how many hours will it take 2 type r machines and 3 type b machines working together and independently to complete the job ? 
Options: a ) 1 / 5 , b ) 29 / 35 , c ) 5 / 6 , d ) 35 / 29 , e ) 35 / 12
Output (English): d