AMC12 2011 A

AMC12 2011 A · Q1

AMC12 2011 A · Q1. It mainly tests Money / coins, Arithmetic misc.

A cell phone plan costs $20$ dollars each month, plus $5$ cents per text message sent, plus $10$ cents for each minute used over $30$ hours. In January Michelle sent $100$ text messages and talked for $30.5$ hours. How much did she have to pay?

一个手机套餐每月收费$20$美元，另外每发送一条短信收费$5$美分，另外超过$30$小时的通话时间每分钟收费$10$美分。1月份，Michelle发送了$100$条短信，并通话$30.5$小时。她需要支付多少钱？

(A) $24.00 $24.00

(B) $24.50 $24.50

(D) $28.00 $28.00

(E) $30.00 $30.00

Answer

Correct choice: (D)

正确答案：（D）

Solution

The base price of Michelle's cell phone plan is $20$ dollars. If she sent $100$ text messages and it costs $5$ cents per text, then she must have spent $500$ cents for texting, or $5$ dollars. She talked for $30.5$ hours, but $30.5-30$ will give us the amount of time exceeded past 30 hours. $30.5-30=.5$ hours $=30$ minutes. Since the price for phone calls is $10$ cents per minute, the additional amount Michelle has to pay for phone calls is $30*10=300$ cents, or $3$ dollars. Adding $20+5+3$ dollars $\boxed{\$28 \textbf{ (D)}}$.

Michelle的手机套餐基础费用是$20$美元。如果她发送了$100$条短信，每条短信收费$5$美分，那么短信费用为$500$美分，即$5$美元。她通话了$30.5$小时，超过$30$小时的部分为$30.5-30=0.5$小时，即$30$分钟。由于通话超时部分每分钟收费$10$美分，因此超时通话费用为$30\cdot 10=300$美分，即$3$美元。总费用为$20+5+3$美元，即$\boxed{\$28 \textbf{ (D)}}$。

Topics