Answer:
adding 12.5
Step-by-step explanation:
12.5 --> 25 through +12.5
25 --> 37.5 through +12.5
37.5+12.5 = 50 = 50
You are adding 12.5 every time.
12.5+12.5=25
25+12.5= 37.5
37.5+12.5=50
Hope this helps!