The lengths of the Tsing Ma Bridge (A), the Kap Shui Mun Bridge (B) and the Ting Kau Bridge (C) are around 2.2 km, 0.8 km and 1.2 km respectively.
a) Find the ratio of the lengths of A, B and C.
b) Mr. Chan drives through these three bridges at the same speed. If he drives through the Ting Kau Bridge in 72 seconds, how long does he take in total to drive through the other two brieges?
請教教我和解釋一下如何計算, 萬分之感謝.
F.1 Maths (Urgent)
2010-05-01 8:39 pm
回答 (2)
2010-05-01 9:07 pm
✔ 最佳答案
a)Ratio of the lengths of A, B and C
= 2.2 : 0.8 : 1.2
= 11 : 4 : 6
b) How long does he take in total to drive through the other two brieges?
He need 72 seconds to travel 1.2km, that means, he is travelling in the speed of
60km/ hr , now , he need to travel 2.2+0.8=3km , that means
he need (3/60) hr = 3 min
OR
in ratio,
he need (72/6) x (11+4) = 180 second = 3 minute
to travel through the other two brieges (A and B)
參考: me
2010-05-01 9:00 pm
a. The ratio of lengths of A, B and C
2.2 ： 0.8 ：1.2
Ratio 指比例，三條橋的長度都是用 km，所以可以就以三個數互比便可。
「：」這附號是 ratio 「比例」的意思。
在計算時，「：」就如「÷」。
b. Ting Kau Bridge is 1.2 km, if he drive through it takes 72 seconds, then, Mr Chan speed:
1.2 ÷ 72 = 1/60 km/s
The total length of all three bridge is 2.2 + 0.8 + 1.2 = 4.2
Therefore, the total time that he needs:
4.2 ÷ 1/60 = 252 seconds
If use ratio in your calculation, it will be:
1.2 ：72 = (2.2+0.8+1.2)：?
?=72 x (2.2+1.8+1.2)÷1.2
?=252 (seconds)
2.2 ： 0.8 ：1.2
Ratio 指比例，三條橋的長度都是用 km，所以可以就以三個數互比便可。
「：」這附號是 ratio 「比例」的意思。
在計算時，「：」就如「÷」。
b. Ting Kau Bridge is 1.2 km, if he drive through it takes 72 seconds, then, Mr Chan speed:
1.2 ÷ 72 = 1/60 km/s
The total length of all three bridge is 2.2 + 0.8 + 1.2 = 4.2
Therefore, the total time that he needs:
4.2 ÷ 1/60 = 252 seconds
If use ratio in your calculation, it will be:
1.2 ：72 = (2.2+0.8+1.2)：?
?=72 x (2.2+1.8+1.2)÷1.2
?=252 (seconds)
收錄日期: 2021-04-16 00:04:41
原文連結 [永久失效]:
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