The task is to generate the correct answer for a given math problem.
--------
Question: Problem: two trains each 120 m in length each , are running on two parallel lines in opposite directions . if one goes at the speed of 85 km / h while the other travels at 65 km / h . how long will it take for them to pass each other completely .

Answer: 10.07 sec

Question: Problem: a certain elevator has a safe weight limit of 2,000 pounds . what is the greatest possible number of people who can safely ride on the elevator at one time with the average ( arithmetic mean ) weight of half the riders being 200 pounds and the average weight of the others being 230 pounds ?

Answer: 9

Question: Problem: a cistern has a leak which would empty the cistern in 20 minutes . a tap is turned on which admits 5 liters a minute into the cistern , and it is emptied in 24 minutes . how many liters does the cistern hold ?

Answer:
60