The task is to generate the correct answer for a given math problem.
--------
Question: Problem: how many seconds will a train 120 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph ?

Answer: 27 sec

Question: Problem: two trains travel in opposite directions at 36 kmph and 45 kmph and a man sitting in slower train passes the faster train in 12 seconds . the length of the faster train is

Answer: 270 m

Question: Problem: a certain protective additive increases from 50 days to 60 days the time between required maintenance checks on an industrial vehicle . by what percent is the time between maintenance checks increased by using the additive ?

Answer:
20