AMC12 2006 B

AMC12 2006 B · Q11

AMC12 2006 B · Q11. It mainly tests Fractions, Mixture / concentration.

Joe and JoAnn each bought 12 ounces of coffee in a 16-ounce cup. Joe drank 2 ounces of his coffee and then added 2 ounces of cream. JoAnn added 2 ounces of cream, stirred the coffee well, and then drank 2 ounces. What is the resulting ratio of the amount of cream in Joe's coffee to that in JoAnn's coffee?

Joe 和 JoAnn 各买了 12 盎司的咖啡，装在 16 盎司的杯子里。Joe 喝了 2 盎司咖啡，然后加了 2 盎司奶油。JoAnn 加了 2 盎司奶油，充分搅拌咖啡，然后喝了 2 盎司。Joe 的咖啡中奶油量与 JoAnn 的咖啡中奶油量的比值为多少？

(A) \frac{6}{7} \frac{6}{7}

(B) \frac{13}{14} \frac{13}{14}

(D) \frac{14}{13} \frac{14}{13}

(E) \frac{7}{6} \frac{7}{6}

Answer

Correct choice: (E)

正确答案：（E）

Solution

Joe has 2 ounces of cream, as stated in the problem. JoAnn had 14 ounces of liquid, and drank $\frac{1}{7}$ of it. Therefore, she drank $\frac{1}{7}$ of her cream, leaving her $2*\frac{6}{7}$. $\frac{2}{2*\frac{6}{7}}=\frac{7}{6} \Rightarrow \boxed{\text{(E)}}$

Joe 有 2 盎司奶油，如题所述。 JoAnn 有 14 盎司液体，并喝掉了其中的 $\frac{1}{7}$。因此，她喝掉了她奶油的 $\frac{1}{7}$，剩下 $2*\frac{6}{7}$。 $\frac{2}{2*\frac{6}{7}}=\frac{7}{6} \Rightarrow \boxed{\text{(E)}}$

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