小學校長安排我每週二和週四到一位有學習困難的學生家裏當家教。昨天是第二天。當我翻閱她的科學和數學課本，不斷在冒汗。天啊！Grade 7 （中二）的生物和數學可以這麼難的？我念這兩門科目是20年前的事了。而且，當時我的學習成績很爛，理科都是及格與不及格之間徘徊。
把我嚇壞的兩道題目是這樣的：
1) 時速100km，走完了160km。現在把速度減慢為時速90km。問格外多花多少時間才能走完160km。是否多花10% 的時間就好了?
2) 植物和動物的細胞有什麼異同？
臨走前我自動投案，告訴家長我不太勝任。她有點錯愕，但是她還是邀請我下禮拜二再來。到時候再告訴我是否有別的安排。
“書到用時方恨少！ ” 這話對極了。
since 24 july 2007, i've started making toronto my home. this blog may allow you to know more about my new life here.
About Me
- Felix Cheng
- Toronto, ON, Canada
- a language teacher who is fond of learning and teaching languages
3 comments:
相信你一定行的！
记住为郑氏宗祖争光！！
I can't tell the answer for the second one, but think it shouldn't be too hard to find the answer from the web (e.g. Wikipedia, etc).
For the first one, it is indeed not that difficult. It is testing your knowledge about inverse proportion relationship.
Speed (S) = Distance traveled (D) / Time (T)
or D = ST.......(1)
Now S' = 0.9 S (i.e. 90 km/h vs 100 km/h)
D is constant. You need to find T' (i.e. the adjusted time required given the lower speed).
S' = D/T'
i.e. 0.9S = D/T'
or D = 0.9ST'........(2)
Equating (1) & (2), you have -
ST = 0.9ST'
so, T' = T/0.9
or about 111% of T.
So the answer is, the time taken will be about 11% more, not 10%.
Don't panic. Stay calm and you'll usually find the answer. They are not as difficult as they look.
Also, the key thing is, it helps a ton if you read the textbook first.
...(con't)
Once you know the topic (say, inverse proportion relationship), it becomes much easier. Also, there usually are examples in the textbook, and the exercise questions are mostly simply a replicate by replacing just the figures!
Chung
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