prep数学24

cyvivi

24.     
In a certain game, the units of currency of three countriesare the crown, the shield, and the pound, respectively.  If 2 crowns equal 3 shields and 3 shieldsequal 4 pounds, how many crowns equal 18 pounds?

(A)  9
(B) 16
(C) 18
(D) 32
(E) 36
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【答案】A

【思路】2c=3s,3s=4p
       4p=18,p=4.5
       3s=18,s=6
       代入2c=3s,c=9



为什么是4p=18?不应该是p=18吗？

vansonkated

题目问：how many crowns equal 18 pounds?

2 crowns equal 3 shields and 3 shields equal 4 pounds

也就是说2 crowns equal 4 pounds
用比例法：2/4= X/18  求得X=9