AMC12 2011 B

AMC12 2011 B · Q3

AMC12 2011 B · Q3. It mainly tests Arithmetic misc.

LeRoy and Bernardo went on a week-long trip together and agreed to share the costs equally. Over the week, each of them paid for various joint expenses such as gasoline and car rental. At the end of the trip it turned out that LeRoy had paid A dollars and Bernardo had paid B dollars, where $A < B.$ How many dollars must LeRoy give to Bernardo so that they share the costs equally?

LeRoy 和 Bernardo 一起进行了一次为期一周的旅行，并同意平分费用。在这一周中，他们各自支付了各种共同开销，如汽油费和租车费。旅行结束时，LeRoy 支付了 $A$ 美元，Bernardo 支付了 $B$ 美元，其中 $A < B$。LeRoy 必须给 Bernardo 多少美元才能使他们平分费用？

(A) \dfrac{A+B}{2} \dfrac{A+B}{2}

(B) \dfrac{A-B}{2} \dfrac{A-B}{2}

(D) B-A B-A

(E) A+B A+B

Answer

Correct choice: (C)

正确答案：（C）

Solution

The total amount of money that was spent during the trip was \[A + B\] So each person should pay \[\frac{A+B}{2}\] if they were to share the costs equally. Because LeRoy has already paid $A$ dollars of his part, he still has to pay \[\frac{A+B}{2} - A =\] \[= \boxed{\frac{B-A}{2} \textbf{(C)}}\]

旅行期间总共花费了 \[A + B\] 因此如果要平分费用，每个人应支付 \[\frac{A+B}{2}\] 由于 LeRoy 已经支付了 $A$ 美元，他还需要支付 \[\frac{A+B}{2} - A =\] \[= \boxed{\frac{B-A}{2} \textbf{(C)}}\]

Topics

AR.015 Arithmetic misc