prep ps1-163

163.      17076-!-item-!-187;#058&010995

In 1990 the budgets for projects Q and V were $660,000 and $780,000, respectively.  In each of the next 10 years, the budget for Q was increased by $30,000 and the budget for V was decreased by $10,000.  In which year was the budget for Q equal to the budget for V ?

(A) 1992

(B) 1993

(C) 1994

(D) 1995

(E) 1996

答案是b,怎么可能阿。。。

我想，你应该是用等差数列解出来N=4，所以答案是第四年，即1994年吧。我开始也是这样想的，后来发现不对。因为等差数列的An应该是这样：

这样可以看出，实际上数列中的A4对应的是1993年。

希望我有讲明白 呵呵

设经过x年，q和v的budget相等

660,000+30,000x=780,000-10,000x

解出x=3，用1990+3=1993

In each of the next 10 years，“在未来十年的每一年中"，楼主是不是这句话理解错误了？