The ratio of glue sticks to glue bottles is 5:2 meaning for every 5 glue sticks there are 2 glue bottles. You have 35 glue sticks which is 7 times 5. Since you did times 7 to one side you must do it to the other, 2*7 is 14. There are 14 glue bottle in the classroom. You can simplify this as well. 35:14 is also known as 35/14 which is simplified to 5/2, equivalent to 5:2