出纳员点一叠20元和50元的人民币共50张，总钱数是1900元，请你算出50元和20元的人民币各有多少张？

推荐阅读：
Depth First Search and Breadth First Search Algorithm to Open th　 Dynamic Programming (Memoization) to Sort Integers by The Power 　 Applicable Accounting Software For Churches　 How to Balance a Binary Search Tree using Recursive Inorder Trav　 Finding the Lucky Numbers in a Matrix　 Factory Design Pattern in Object Oriented Design Programming　 Algorithm to Find Minimum Removals to Make Valid Parentheses　 Greedy Algorithm to Validate Stack Sequences　 Why is Web Hosting Important for Bloggers?　 How to Write More Local Content (and Why You Should)