单选题Seven years ago, Scott was 3 times as old as Kathy was at that time. If Scott is now 5 years older than Kathy, how old is Scott ?A12.5B13C14D14.5
单选题
Seven years ago, Scott was 3 times as old as Kathy was at that time. If Scott is now 5 years older than Kathy, how old is Scott ?
A
12.5
B
13
C
14
D
14.5
参考解析
解析:
这是一道稍复杂的计算题,设Scott七年前的年龄为X,则有X+7-(1/3X+7)=5,由此可得X=7 1/2,再加上7即是Scott现在的年龄,因此该选14.5。
这是一道稍复杂的计算题,设Scott七年前的年龄为X,则有X+7-(1/3X+7)=5,由此可得X=7 1/2,再加上7即是Scott现在的年龄,因此该选14.5。
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