In a fruit punch drink, the 3 ingredients are apple juice, orange juice and cranberry juice. If 1/4 of the drink is apple juice and 2/5 is orange juice then write the ratio of cranberry juice to apple juice to orange juice in its simplest form.
You have to add 1/4 and 2/5 which gets you 13/20. And since the glass would be full, 20/20 is full, so then you have to subtract 20/20 from 13/20 which gives you 7/20.