Instructions: In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Input: Problem: two pipes can fill a tank in 20 minutes and 12 minutes . an outlet pipe can empty the tank in 10 minutes . if all the pipes are opened when the tank is empty , then how many minutes will it take to fill the tank ? 
Options: a ) 24 , b ) 26 , c ) 28 , d ) 30 , e ) 32
Output:
d