My answer in your question is 25 & 5/8 or 25.625 ....how to get?? .... .Here are trivias for you: 11& 3/4 = 47/4 13 & 7/8 = 111/8 Get the greatest common factor.. that is 8 so: 11& 3/4 = 46/4 = 94/8 13 & 7/8 = 111/8 Just add them; 94/8 + 111/8 = 205/8 205/8 = 25 & 5/8 or 25.625