Task: Question Answering
Input (English): Problem: in a certain animal shelter , the ratio of the number of dogs to the number of cats is 15 to 7 . if 20 additional cats were to be taken in by the shelter , the ratio of the number of dogs to the number of cats would be 15 to 11 . how many dogs are in the shelter ? 
Options: a ) 75 , b ) 25 , c ) 30 , d ) 45 , e ) 60
Output (English): a