A sum of $200,000 from a certain estate was divided among a spouse and three
children. How much did the youngest child receive?
(1) The spouse received 1/2 of the sum from the estate, and the oldest child
received 1/4 of the reminder
(2) Each of the two younger children received 12,500 more than the oldest
child and 62500 less than the spouse
[解]假設母親拿A，三個孩子(由大到小)分別拿B, C, D，
可以得到 A + B + C + D = 200,000。題幹欲判斷D值是否能求出。
(1)A=200,000*(1/2)=100,000，
B=100,000*(1/4)=25,000，
以上代入原式，
得到 100,000 + 25,000 + C + D = 200,000，
無法解出 C 與 D，
條件不充分;
(2)由條件可知，C = D = A - 62,500 = B + 12,500，
將四人都以C表示，
得到： A + B + C + D = ( C + 62,500 ) + ( C - 12,500 ) + C + C = 200,000，
C可以求出，D也可以求出。
條件充分;
選B。
