Question

SAT两道数学题求解答!!!

1.At time t=0,a ball was thrown upward from an initial height of 6 feet. Until the ball hit the ground, its height, in feet, after t seconds was given by the function h above, in which c and d are positive constants. If the ball reached its maximum height of 106 feet at time t=2.5, what was the height, in feet, of the ball at time t=1?
答案是70

2.The Acme Plumbing Company will send a team of 3 plumbers to work on a certain job.The company has 4 experienced plumber and 2 trainees, how many different such teams are possible?
答案是24
哎呀傻了= =

方程：h(t)=c-(d-4t)^2

Answer 1

第一题你没有把h那个方程写上来，题目中说上面给出了h的方程。

第二题就是个概率组合，怎么算都不是24啊。
如果是一个trainee带三个plumbers，就是8
如果是一个trainee带两个plumbers是12
如果不分plumbers和trainees，就是在6个人里面选3个，那就是20

追问

我也是算了20！！！
可是答案的确是写24的

追答

那就是答案有问题吧。呵呵

追问

应该也是~好心人能不能帮我看看第二题。。。

Answer 2

h(t)方程式将t=0 h=6, t=2.6 h=106代进去解方程
不过估计你已经上了大学一年多了。。

Answer 3

孩子，你这个第二题都打都打错了。你回去看看题。正解应该是24. C 4 1 * C 4 2=24

Answer 4

看都看不懂