1 2 3 4 5 6 7 8 9 = 100
Challenge:
Place + and - math symbols between the numbers above to make the equation true.
Use + and - a total of three times.
Do not rearrange the numbers.

Two stations A and B are 110 km apart on a straight line. One train starts from A at 7 a.m. and travels towards B at 20 kmph. Another train starts from B at 8 a.m. and travels towards A at a speed of 25 kmph. At what time will they meet?