會考Maths 問題. Two Questions.

2008-03-17 3:04 am

大家,
我做mathematics exercise時遇到一d問題 , 希望你地可以幫到我:

Question 1 :

A & B measured the length and the width of a basketball court. The court found by Ming is 28m, correct to the nearest 0.25 m ; whereas the width found by Miu is 15 m, correct to the nearest 0.2m .

( a ) Find the Maximum error & percentage error of the measured length and width.

( b ) Which measuerment is more accurate? Why?

( c ) Find the lower limit and upper limit of the area of the basketball court.

Question 2 :

A bottle of surgical spirit contains alcohol up to 75% of its volume. The remaining cotent is water. If 3 litres of water is added, the percentage of alcohol will decrease to 45%. Find the original volume of that bottle of surgical spirit.

回答 (1)

Chui Ling

2008-03-18 9:46 am

✔ 最佳答案

For Q1, I don't know what exactly you mean. So can you clarify it?

For Q2,
Let the original volume of that bottle of surigical spirit be x cm^3
0.75x / (x+3000) = 0.45
0.75x = 0.45x + 0.45 * 3000
0.3x = 0.45 * 3000
x = 0.45 * 3000 / 0.3 = 4.5 * 1000 = 4500
so the original volume of that bottle of surigical spirit is 4500 cm^3 (4.5L)

參考: myself

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