lisaislisa

同意以上 ^^辛苦
下周我来吧

^^

lisaislisa

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1. 共78个大人参加一个带小孩去的野炊之类的活动，其中35个自愿照看小孩，有11个自愿又照顾小孩又带吃的，现在告诉已知自愿带吃的大人的数量是既不照看小孩，又不带吃的大人的数量的1。5倍，问带吃的大人有多少？
【确定】36
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I wonder sth wrong with the number ...,my ans is 54/2.5*1.5 which is not a integer , moreover , with the ans of 36 , thoses willing to take food is TWICE the number of those neither willing to take care of the kids nor willing to take food...but not 1.5 times

how come ?...

^^
[em26]  [em26]  [em26]  [em26]   [em26]   [em26]
that's the sunshine for SH today !

lisaislisa

thx for your explain victor
and Jean
here is another problem from drlucky
How many of the numbers x, y, and z are positive? x, y, and z are all less than 30.
(1) x + y + z = 61
(2) x + y = 35
Thx,
--------------------------------
ans is A , how come ?...

^^

lisaislisa

谢谢猫猫 ^^
可我不太明白什么叫做How many of the numbers x, y, and z are positive?

^^

lisaislisa

agree with victor ^^

lisaislisa

How many of the numbers x, y, and z are positive? x, y, and z are all less than 30.
(1) x + y + z = 61
(2) x + y = 35
Thx,
--------------------------------
这个how many 是指有几个满足?
如果1)就足够,那么又有多少 x y z 满足呢?

[em06]   [em27]   [em06]   [em27]   [em06]

有两个不同SCALE的刻度，30对应6；60对应24；问100应该对应多少啊？
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现在我脑子里有一幅图 好比投影
30 到 60 放大两倍
6 到 24 放大 4倍
继续 60 到 100 10/6 倍
所以 24 的 20/6 倍 就是 80
可是两者有线形关系吗? I wonder ....

[em22][em13][em10][em02][em23][em05][em28][em19]

lisaislisa

How many of the numbers x, y, and z are positive? x, y, and z are all less than 30.
(1) x + y + z = 61
(2) x + y = 35
Thx,
这题的答案是a哎 总觉得这题怪怪的, 那有这种问法的...;p

to M022girl
不懂你的意思....请再详细些
^^

lisaislisa

哦 知道你是什么意思了
可是要得到50 必须有5或10
所以是重复计算了

^^

lisaislisa

3. There are 20 cars in a dealershop, the cars are of 5 different colors including white cars and red cars. The probablility of picking either a white or red car is less than 3/5. What is the greatest possible number of red cars? [思路]求红车数目的最大可能 已经知道The probablility of picking either a white or red car is less than 3/5 小于3/5的最大的数是4/5 -——》R/20=4/5 红车数目的最大可能是16 ------------------------ how come 4/5is greater than 3/5 i think , if there is at most 3/5 cars are either white or red then the number of white plus red is less than 12 the biggest possible is 11 then at least there should be on white car so the possible largest number of red car is 10 5. What is the value of integer r? a) 4<(r-1)(r-1)<16 b) 4<(r+1)(r-1)<16 ---------------------------- a)=>2 -1 integer r =-2 or 4 b)=>4<5 -root17 r=-4 ,-3 or 3 ,4 combine a)and b)=> r=4 my an is C others agree ^^

lisaislisa

Mush : it makes sense !
thx for your warning

^^