题干

京津城际铁路将于2008年8月1日开通运营,预计高速列车在北京、天津间单程直达运行时间为半小时.某次试车时,试验列车由北京到天津的行驶时间比预计时间多用了6分钟,由天津返回北京的行驶时间与预计时间相同.如果这次试车时,由天津返回北京比去天津时平均每小时多行驶40千米,那么这次试车时由北京到天津的平均速度是每小时多少千米?
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答案(点此获取答案解析)

这次试车时,由北京到天津的平均速度是每小时200千米

解答:设这次试车时,由北京到天津的平均速度是每小时x千米,则由天津返回北京的平均速度是每小时(x+40)千米.依题意,得 = (x+40),解得x=200.

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    When my friend Lesa was diagnosed(诊断) with cancer, another friend and I went to the hospital to spend some time with her. We bought her a small toy and  named him Lemon-Aide. We gave Lemon-Aide to Lesa and told her he was to go with her to all of her treatments to remind her that we were thinking of her and caring about her even though we could not always be with her. When the treatments were completed, she said when someone else needed him she would pass him along.

    A few months later, much to my surprise, it was me that she passed him to. Lemon-Aide went with me to all of my treatments.

    One day while waiting for my doctor I decided we could market the idea to fight cancer. Lesa thought it was a great idea so we founded the organization that came to be known as Lemon-Aide's Friends, Inc. We designed our organization to remind people fighting cancer that there are people who love and care about them all the time. Today we have totally 5013 volunteers. The money raised is donated to cancer patients who do not have insurance. The physicians on our Board of Advisors determine how and where our money is donated.

    Lemon-Aide is for men, women, and children of all ages and to date has been sent to 34 states and 33 countries to provide smiling support for people fighting cancer. When life gave us lemons we made Lemon-Aide, a soft smiling toy that represents love, support, and encouragement.