how do ratios work

ratios are just fractions not written in fraction form, for example 8:9 ratio just means the first value is 8/(8+9) and the second value is 9/(8+9)if a question says that in a ratio of green apples to red apples 7:2, there are 16 red apples,it just means that 16 = 2/(7+9) which is 16 = 2/9the easiest way i find is to find the value of 1/9, which would be 8and then using the value of 1/9 u can find how much green apples there are, whichi is 8x7=56