The answer is:
25 / 0.5 = 50
Or in fraction form:
[tex]\bf~\frac{25}{1} / \frac{1}{2} = \frac{50}{2} / \frac{1}{2} = \frac{50}{2} * \frac{2}{1} = \frac{100}{2} = 50[/tex]
Hope it helped,
BioTeacher101
(If you have any questions, feel free to ask them in the comments)