The task is to generate the correct answer for a given math problem.
--------
Question: Problem: in a group of 150 readers who read science fiction or literacy works or both , 120 read science fiction and 90 read literacy works . how many read both science fiction and literacy works ?

Answer: 60


Question: Problem: two trains of equal length , running with the speeds of 60 and 90 kmph , take 50 seconds to cross each other while they are running in the same direction . what time will they take to cross each other if they are running in opposite directions ?

Answer: 6.6


Question: Problem: the sum of first 45 natural numbers is

Answer:
1035