Scanning the Pages of a Book

Welcome! You are encouraged to register with the site and login (for free). When you register, you support the site and your question history is saved.

One scanning device, working at a constant rate, can scan the pages of a particular book in 11 minutes. A second scanning device, working at a constant rate, can scan the same book in 5 minutes. If both scanning devices are used on different copies of the book, one working from the front and one from the back, approximately how many minutes are required to scan the pages of the book?

Review: Scanning the Pages of a Book


Explanation

The rates here are measured in either pages per minute or books per minute. We can use pages and call P the number of pages in this book. The combined rate of using both scanners will be the sum of their individual rates:



The variable P cancels out and we can multiply both sides by 55x:







Since , this fraction equals "three point something."

The correct answer is (D).


If you believe you have found an error in this question or explanation, please contact us and include the question title or URL in your message.
Continue »