I think that your answer would be 3 and 3/4 cups. I think cause 1 cup +1cup+1cup equals 3 cups so that would be the whole number then 1/4+1/4+1/4 equals 3/4 cups so that would be your fraction then all is needed to do it put then in the order. So three and three-fourth is your answer. (3 and 3/4).
If you need to put them into a mixed number all you have to do is take the denominator of the fraction (4) and multiply that to the whole number (3) and once that is done you would want to take the number that you just multiplied (which 4 x 3 =12) so then you would add ( 12+3=15) so then the 15 would go on the top and 12 on the bottom and your answer would come out to be as a mixed number so 15 / 12 is the mixed number. ( I think that is how you would change a fraction to a mixed number.- again i think)
~Hope this helps!~