does anyone know how to do this

1. 25%
2. unsure
[tex]\frac{25}{100} +\frac{20}{100} = \frac{45}{100} or \frac{9}{20}[/tex] (this is #3)
4. [tex]\frac{25}{100} + \frac{10}{100} = \frac{35}{100} or \frac{7}{20}[/tex] (not sure if you're supposed to use a fraction, so this might be wrong)
5. unsure