四月三号上午场，少量狗狗（整理寂静的同学再仔细看看吧）

flyingbunny

第6题绝对不是 [g(100-t)- s](100-c)/10^4

davidleezone

楼主是这个么？During the month of May, crabs arrive on Delaware’s beaches to lay eggs.  Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds.  Delaware’s crab population has declined recently.  This decline, however, poses no serious threat to the migrating shorebird populations:  by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.

jessie10

an  = an-1   +  2an-2然后给出a1=2, a2=3 ， 求前五项的和。


这题是不是52呀？

Avène

谢谢分享

jessie10

第6题绝对不是 [g(100-t)- s](100-c)/10^4

-- by 会员 flyingbunny (2010/4/3 22:32:21)

那是不是 [g(100-c)-100s](100-c)/10^4?

jessie10

就是提到溶液的，说X吨20%浓度的solution和Y吨60%浓度的solution能够配200吨30%的solution,问Y等于多少


这题是用X来表示Y吗？ 还是答案给出具体数字的？

ttss

就是提到溶液的，说X吨20%浓度的solution和Y吨60%浓度的solution能够配200吨30%的solution,问Y等于多少


这题是用X来表示Y吗？ 还是答案给出具体数字的？

-- by 会员 jessie10 (2010/4/3 22:58:05)

选项都是数字，这题我也考了

szzhengly

就是提到溶液的，说X吨20%浓度的solution和Y吨60%浓度的solution能够配200吨30%的solution,问Y等于多少


这题是用X来表示Y吗？ 还是答案给出具体数字的？

-- by 会员 jessie10 (2010/4/3 22:58:05)

这题很简单：   x+y=200
                      0.2x+0.6y=200*0.6
解方程组~

szzhengly

楼主是这个么？During the month of May, crabs arrive on Delaware’s beaches to lay eggs.  Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds.  Delaware’s crab population has declined recently.  This decline, however, poses no serious threat to the migrating shorebird populations:  by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.

-- by 会员 davidleezone (2010/4/3 22:33:00)

对，是这题

szzhengly

an  = an-1   +  2an-2然后给出a1=2, a2=3 ， 求前五项的和。


这题是不是52呀？

-- by 会员 jessie10 (2010/4/3 22:49:46)

是的