题目
Two painters, Ray and Taylor, are painting a fence. Ray paints at a uniform rate of 40 feet every 160 minutes, and Taylor paints at a uniform rate of 50 feet every 125 minutes. If the two painters paint simultaneously, how many minutes will it take for them to paint a fence that is 260 feet long?
解析
我们先确定每个人**每分钟**能刷多少围栏:
**雷的刷漆速率是每160分钟刷40英尺**
计算:\( \frac{40\text{英尺}}{160\text{分钟}} \)
上下同时除以160,得:\( \frac{0.25\text{英尺}}{1\text{分钟}} \)
所以,雷每分钟能刷0.25英尺
**泰勒的刷漆速率是每125分钟刷50英尺**
计算:\( \frac{50\text{英尺}}{125\text{分钟}} \)
上下同时除以125,得:\( \frac{0.4\text{英尺}}{1\text{分钟}} \)
所以,泰勒每分钟能刷0.4英尺
因此,两人**一起工作**时,每分钟能刷 \( 0.25 + 0.4 = 0.65 \) 英尺
**刷完260英尺的围栏需要多少分钟?**
时间 = 总量 ÷ 速率
\( = 260 ÷ 0.65 \)
\( = 400 \) 分钟
答案:B