form two maths

2007-08-09 1:38 am

q.1 a rectangle aquarium of dimensions 27m X 12m X 2.5m is full of water . how long will it take for the pumping machine to pump way 1 over 3 of the water in the aquarium?

q.2 a copper wire 108 cm long is bent to form a triangle, in which the lengths are in the ratio 3:4:5 . find the length of the longest side of the triangle.

回答 (1)

abaform

2007-08-09 4:57 am

✔ 最佳答案

Q1: In this question there is some parameter missing: the rate of flow of water
Let k m^3/s be the rate of flow of water. Then the time it takes for the pumping machine to pump away 1/3 of the water will be
(27m x 12m x 2.5m) / (k m^3/s) = (810/k) s

Q2: Let the lengths of the 3 sides be 3k, cm 4k cm, 5k cm, where k is a positive real number. Then, we can set the equation
3k + 4k + 5k = 108
12k = 108
k = 9
The lengths of the 3 sides are 27cm, 36cm and 45cm.
The longest side of the triangle is 45cm.

2007-08-08 20:59:15 補充：
For question 1, there is some modificationThe time it takes for the pumping machine to pump away 1/3 of the water should be (27m x 12m x 2.5m x 1/3) / (k m^3/s) = (270/k) s

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