唔明...

L.K.

一輛貨車從甲地到乙地需8小時，一輛客車從乙地到甲地需6小時，貨車開了兩小時後，客車出發，問客車出發後幾小時兩車相遇？
解　　這題與一般的相遇問題不同，全程多少，沒有具體的量，這時可以設甲地到乙地的路程為“１”，這樣就把行程問題轉化成了工程問題。
　　 貨車一小時走全程的1/8，客車一小時走全程的1/6，貨車走了兩小時後，還有路程為
１－１

piyopiyo

咁唔明d咩[[yoyo_147]]

[S]【YU】

簡單黎講...當全程為 1...
呢條問題,最後全程係會被cancel走,所以是independent的.
就算你let x, 都無問題.

speed A = x/8
speed B = x/6
distance travelled by A in 2 hrs = 2x/8
remaining distance  = x - 2x/6
-----------------------------------------------------------------------------------------------
relative speed = x/6 + x/8
time to meet = (x - 2x/8) / (x/6 + x/8) = 18/7 hrs

or
let t be the time to meet, sum of distance travel = remaining distance
xt/6 + xt/8 = x - 2x/6
u will also get the same result by the same calculation after rearrangment.

[ 本帖最後由 [S]【YU】 於 27-5-2008 10:38 編輯 ]

L.K.

冇野...
明了
睇唔到呢句...--->貨車開了兩小時後....
THX~~~

[ 本帖最後由 L.K. 於 27-5-2008 12:37 編輯 ]

piyopiyo

原帖由 [S]【YU】 於 27-5-2008 10:32 發表
簡單黎講...當全程為 1...
呢條問題,最後全程係會被cancel走,所以是independent的.
就算你let x, 都無問題.

speed A = x/8
speed B = x/6
distance travelled by A in 2 hrs = 2x/8
remaining distance  = x ...

高人果然唔同d[[onion_47]] 一睇就知佢唔明d咩

adamsteve

梗係啦 神級學長  YU就好啦 考完試....
1614 1614 1614

piyopiyo

原帖由 adamsteve 於 27-5-2008 17:02 發表
梗係啦 神級學長  YU就好啦 考完試....
1614 1614 1614

1614的意思是否
BEng (Hons) Mechatronic Engineering?[[onion_44]]樂古真係好多Engine ge人才

[S]【YU】

1614 = ELEC1614 = Course Code of Electronic devices and circuits of EE in HKU....
wt is Mechatronic Engineering ? new thing?

piyopiyo

原帖由 [S]【YU】 於 27-5-2008 17:54 發表
1614 = ELEC1614 = Course Code of Electronic devices and circuits of EE in HKU....
wt is Mechatronic Engineering ? new thing?

唔知wor,路過jupas見到...

其實可能Adamsteve只係求其up d無意思ge數字出泥[[onion_48]]

[ 本帖最後由 piyopiyo 於 27-5-2008 18:06 編輯 ]

adamsteve

唔會啦@@ yu 1614 拎a+架=.=
1614可以話係圍內暗號 原來人地學系係記course名
係好少記course code=.= 搞到我變左異族咁