5 S.1 maths questions(help!)

1.If a:b=2:1 and b:c=2:5, then a:b:c=?
a:b = 2:1 ; b:c = 2:5
∴ a:b:c = 4:2:5
2.Find the rate for the following in the unit indicated:
100km in 8 hours (km/h)
∴ 100 km / 8 h = 12.5km/h
3."3local teams and 5 foregign teams took part in a football competition".A rate or ratio should be used in this case?
∴ A ratio should be used in this case.
4."A car travelled 150km in 2 hours".A rate or ratio should be used in this case?
∴ A rate should be used in this case.
5.The weight of a football player is 88.5kg, correct to the nearest 0.5kg.
I have a question for this question.
∴ The answer is 89.0kg. (88.5→89.0)

2009-07-30 17:34:45 補充：
Sorry, This sentence should be cancelled.

"I have a question for this question."

Thx for your attention.

1. If a:b=2:1 and b:c=2:5, then a:b:c=?

a:b=2:1
b:c=2:5 (The letter B appear in 2 formula)

Find L.C.H (1 AND 2)

a:b=2x2:1x2=4:2
b:c=2:5

Therefore, a:b:c = 4:2:5//

2. Find the rate for the following in the unit indicated:
100km in 8 hours (km/h)

(speed: distance/time)

100/8
=12.5 (km/h)//

3. ."3local teams and 5 foregign teams took part in a football competition".A rate or ratio should be used in this case?

A ratio should be used in this case(3:5)

4. ."A cae travelled 150km in 2 hours".A rate or ratio should be used
in this case?

A ratio should be used in this case (This question type are usually used in rate)

5. The weight of a football player is 88.5kg, correct to the nearest 0.5kg.

88.5kg, correct to the nearest 0.5kg.
=89.0kg//