Form 2 maths(ratio)

各路英雄,請高抬貴手.
6條問題,識答就答,請!

1.A bridge with actual length 0.75 km is shown on a photo with a scale 1cm:100m.

(a) Find the length of the bridge in the photo in cm.

(b)Find the scale of another photo,such that the length of the bridge in it is 15cm.

2.The length of a road on a map with a scale 1cm: 0.25km is 6cm.

(a)Find the actual of the road in km.

(b)Find the length of the road,in cm ,on another map with a scale 1:60000.

3.The length of a certain highway is a cm on a map with a scale 1cm:4.5km and
b cm on another map with a scale 1:250000.What is the ratioof a to b.

4.Amy rides a bicycle from city A to city B at a speed of 30km/h.The distance
between the two cities is measured to be 1.5 cm on a map. If Amy uses 12
minutesto complete the journey, find thw scale of the map in the form 1:n.