Answer:
[tex]\frac{78}{25}[/tex]
Step-by-step explanation:
A rational number has the form
[tex]\frac{a}{b}[/tex] ← where a and b are integers
3.12 = [tex]\frac{312}{100}[/tex] ← divide numerator/denominator by 4, thus
3.12 = [tex]\frac{78}{25}[/tex] ← in simplest form