So you first need to make both equivalent fractions. You do that by making the denominator the same so you need to find a common multiple between both which is 12 so you multiply 2/3 by 4 on the top and bottom to get something equivalent to 7/12. 7/12 +8/12=15/12 now you divide 15 and 12 to have it in fraction mode you’ll be getting that Judy and her sister studied for 1 hour and 25 minutes
