GRE代数文字题：货币问题，在gre数学考试当中，比较常考的一类数学代数问题就是货币问题，对于概率的换算常常让很多考生都出现错误，代数比较注重细节的问题，在做题过程中有一点点的错误就会导致后得不到正确的推算，下面我们就广州英语培训学校一起来看看详细的内容。
货币问题(Currency ( Coin and Bill ) Problems)
Currency problems are really gtuut-weighted-average(准加权平均) problems, because each item(bill or coin ) in a problem is weighted according to its monetary value. Unlike weighted average problems, however, the "average value" of all the bills or coins is not at issue. In solving currency problems, remember the following,
1. You must formulate algebraic expressions involving both number of items ( bills or coins)and value of items.
2. You should covert the value of all moneys to a common unit ( that is, cents or dollars )before formulating an equation. If converting to cents, for example, you must multiply the number of nickels by 5, dimes by 10,and so forth.
【例】: Mike has S 2. 05 in dimes and quarters.If he has four fewer dimes than quarters,how much money does he have in dimes?
解: Letting x equal the number of dimes, x+4 represents the number of quarters. The total value of the dimes ( in cents) is lOx, and the total value of the quarters ( in cents) is 25 (x+4), or 25x+100. Given that Mike has S 2.05, the following equation emerges： 10x+25x+100-205m'x=3 Mike has three dimes, so he has 30 cents indimes.
关键字：GRE代数文字题：货币问题
