问题
单项选择题
已知甲走5步的时问，乙只能走4步，但是甲走5步的距离，乙只要走3步就够了．让甲先走20步，乙再追他，乙要追上甲需要走（）步。
A．24
B．36
C．42
D．48
E．60
答案
参考答案：D
解析：
[*]，甲先走20步，再花时间t走5t，这段时间内，乙走了4t，因为甲走5步的距离乙走3步就够了，所以[*]，得t=12，则4t=48．
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已知甲走5步的时问，乙只能走4步，但是甲走5步的距离，乙只要走3步就够了．让甲先走20步，乙再追他，乙要追上甲需要走（）步。
A．24
B．36
C．42
D．48
E．60
参考答案：D
解析：
[*]，甲先走20步，再花时间t走5t，这段时间内，乙走了4t，因为甲走5步的距离乙走3步就够了，所以[*]，得t=12，则4t=48．
TEENSGIVING in SPRING 2010  Frequently Asked Questions What is TEENSGIVING? TEENSGIVING is an exciting event where hundreds of New York City teens gather together annually for a remarkable day of community service. This year, TEENSGIVING in SPRING 2010 participants will once again better New York City and impact thousands of lives! When is TEENSGIVING in SPRING 2010? SUNDAY, APRIL 25, 2010 Where is TEENSGIVING? All over New York City. Everyone will meet at the 92nd Street Y (92nd and Lexington) at 9:00 AM for the event kick-off. Then, all TEENSGIVING volunteers will disperse across the city to work with our partnering agencies where they will make a HUGE difference (and have fun!). Who participates in TEENSGIVING? Hundreds of teenagers from around the city. Teens come from the 92nd Street Y, various city schools, youth groups, and organizations in the area. In addition, many adult volunteers (ages 21 and older) will donate their time to TEENSGIVING in SPRING 2010. What projects do participants do at the agencies? Sample projects include painting park benches, planting gardens, visiting and playing with underprivileged children, assembling craft kits for children in hospitals, assisting at animal shelters, working at soup kitchens, delivering meals and celebrating with families at homeless shelters. Do I get anything for participating in TEENSGIVING? Yes! Everybody benefits! Teen volunteers will receive *6 hours* of community service credit, good towards honor society, high school graduation and college application requirements. Adult volunteers will be “thanked” with a light breakfast, a gift certificate for their troubles, and the satisfaction of helping our city’s youth contribute to their community. In addition, all teen and adult volunteers will receive a cool TEENSGIVING in SPRING 2010 T-shirt. This sounds awesome! How do I register for TEENSGIVING in SPRING 2010? Interested teens and/or adults should e-mail the TEENSGIVING Coordinator Josh Hyman at jhyman@92Y.org (subject: TEENSGIVING) to receive more information and to register for this fantastic event! **Teens can also contact their school’s Community Service Advisor** TEENSGIVING is sponsored by the 92nd Street Y. 45. TEENSGIVING is an event held ____________.
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