Let's define the next variable:
x: the original second prize (in tickets)
The first time, she won 50 tickets. The second time, she won 4 times the number of tickets of the original second prize, that is, 4x. Altogether she won 200 tickets. That is,
50 + 4x = 200
50 is adding on the left, then it will subtract on the right
4x = 200 - 50
4x = 150
4 is multiplying on the left, then it will divide on the right
x = 150/4
x = 37.5
The original second prize was 37.5 tickets
