Answer:
I don't know the options, but you would find the lowest common denominator as possible, in this case it's 40. so, you figure out how you get from the original denominator to the common one, and then do the exact same thing to the numerators.
and
![(3)/(10) = (12)/(40)](https://img.qammunity.org/2021/formulas/mathematics/high-school/x61s8939is5vke5ozvgzfo7ze2384nrcrw.png)
and then take the two new fractions and subtract the numerators to get what the answer is:
= 0.325
normally you would simplify, but this fraction is already in it's simplest form. so you could convert to a decimal, but only if the directions say to.