The task is to generate the correct answer for a given math problem.

[EX Q]: 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 ?
[EX A]: 6.6

[EX Q]: Problem: a sum was put at simple interest at a certain rate for 10 years . had it been put at 5 % higher rate , it would have fetched rs . 600 more . what was the sum ?
[EX A]: rs . 1200

[EX Q]: Problem: how many liters of a 40 % iodine solution need to be mixed with 35 liters of a 20 % iodine solution to create a 34 % iodine solution ?
[EX A]:
13