It depends on the question, but if the questions is sort of like "Person A and Person B shared 40 sweets in the ratio 3:5, how many sweets did Person A get" then you add 3 and 5 to get 8, and then you do 40 ÷ 8 to get 5 which is 1 in terms of the ratio. Then, you would multiply 5 by 3 to get 15 sweets. If it's a different type of question then let me know so I can help out :)
