Anna, Betsy and Charlene had a total of $$168$$ marbles. Charlene gave $$15$$ marbles to Betsy. Then, Betsy gave $$8$$ marbles to Anna. In the end, the ratio of the number of marbles that Anna had to the number of marbles that Betsy had to the number of marbles that Charlene had is $$2:5:7$$. How many marbles did Betsy have at first? 
Overseas Competition->Knowledge Point->Word Problem Modules->Solving Problems Involving Proportions->Dividing Quantities Based on Ratio