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

[EX Q]: Problem: | x + 3 | – | 4 - x | = | 9 + x | how many solutions will this equation have ?
[EX A]: 1

[EX Q]: Problem: two tains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post . if the length of each train be 120 metres , in what time ( in seconds ) will they cross each other travelling in opposite direction ?
[EX A]: 12

[EX Q]: Problem: by the how much is two - fifth of 300 greater than 3 - fifths of 125 ?
[EX A]:
45