Maths題目 4題(十分趕!!!!!!!!!!)

1.Trapeziums ABCD and PQRS shown on the right are two similar figures. If CD : RS = 4:3, find
(a)the values of x,y and z.
(b)area of ABCD: area of PQRS.

2.Collin and Chris share the typing work of a document such that they both finish thier portion of the document in 5 minutes.It is given that Collin types at 45 words per minute, and the ratio of Collin's typing speed to that of Chris is 9:10.
(a)How many words are there in the entire document?
(b)If they share a document by allocating an equal number of words to words to each person, what is the ratio of the time taken by Collin to the time taken by Chris?

3.A woman rides a hourse from village P to Q at a speed of 24 km/h. The distance between the two villages is measured to be 8 cm on a map. If the woman takes 3 minutes to travel from one village to another, find the scale of the map.

4.When an object of mass m kg moves at a speed of v m/s, its kinetic energy KJ ca be calculated by the following formula:K=1
__mv二次方
2
(a)If an object of mass 2 kg moves at a speed of 8 m/s, what is its kinetic energy?
(b) (i)Make m the subject of the above formula.
(ii)An object moves at a speed of 10 m/s and its kinetic energy is 350 J. What is the mass of the object?