Four questions of Ratio part B (10 marks)

3) A bottle of juice is shared by A,B and C in the ratio of 2:3:5. If C gets 750mL of juice, find the volume of juice in the bottle.

750 ÷ [ 5/( 2+3+5)]
= 750 x (10 / 5)
= 1500 //

The volume of juice in the bottle is 1500mL

4) The ratio of the numbers of red, yellow and blue marbles in a bag is 2:1:6. If there are 18 red marbles, find

a) the total number of marbles.
18 ÷ [ 2 / ( 2+1+6)]
= 18 x ( 9/2 )
= 81 //

The total number of marbles is 81.

b) Find the number of blue marbles in the bag.
81 x [6 /( 2+1+6)]
= 81 x (6 / 9)
= 54 //

The number of blue marbles in the bag is 54

2007-02-06 18:35:18 補充：
~上面那位計錯第一題

2007-02-06 21:29:30 補充：
我想回應下第一位回答者的解答方式先~佢首先係把各樣object的value搵出來, 再將它們加起來, 計出total, 但我認為這種方法要寫多幾個steps, 較花時間, 但如果一式過, 寫晒出黎, 會冇咁麻煩, 老師睇起黎亦方便D雖然他的方法比起一式過的方法唔係太common, 不過都係ok的~只係技巧上有丁丁出入[ 以上全屬本人的意見, 只供參考用途 ]

3) The volume of juice in the bottle: 750 mL ÷ 5 X ( 2+3+5)=150mL X 10=1500mL
4a)The total number of marbles: 18 ÷ 2 X (2+1+6)= 9 X 9= 81
4b)The number of blue marbles in the bags: 81 ÷ (2+1+6) X 6= 81 ÷ 9 X 6=9 X 6=54

3)Let the volume of juice in the bottle be y

y(5/2+3+5)=750

y(5/10)=750

y=1500

the volume of juice in the bottle=1500mL

4)a)let y be the total number of marbles
y(2/2+1+6)=18
y(2/9)=18
y=81

the total number of marbles.=81

b)the number of blue marbles in the bag
=81(1/2+1+6)
=81(1/9)
=9

1) Suppose X is the volume in the bottle,
C gets (5/2+3+5)X=X/2=750mL
So, X=1.5L

2a) Suppose the total number of marbles be T,
(2/2+1+6)T=2/9T=18, T=81

2b) Number of blue marbles = 6/(2+1+6)xT=2/3x81=54

3. 5c = 750 , c = 150

so 2(150 ) = 300 , 3 (150 ) = 450

4. 2x = 18 , x =9

1(9) = 9 , 6(9) = 54

a) 18+9+54 = 81

b) blue : 6(9) = 54