maths

Simplify each of the following ratios.
1a.0.625:25/16
0.625:25/16
= 10:25
= 2:5

b.1 hour 15 min:45 min
1 hour 15 min:45 min
= 75min : 45min
= 5 : 3

c.40c㎡:1600m㎡
40c㎡:1600m㎡
= 40c㎡ : 1600/100 c㎡
= 40 : 16
= 5 : 2

d.225%:3/8:3
225%:3/8:3
= 2.25：0.375：3
= 18：3：24
= 6：1：8

2a,32:28=12:x
32:28=12:x
32x = 12*28
x = 10.5

b.3/2:y=8:3
3/2:y=8:3
8y = (3/2)(3)
16y = 9
y = 9/16

c.2:p:3/4=q:4:24
2:p:3/4=q:4:24
2/q = (3/4)/24
(3/4)q = 48
q = 64
p/4 = (3/4)/24
24p = 3
p = 1/8

3.If a sum of $6650 is to be divided into 3 portions in the ratio of 1/3:2/3:3/8,find the largest amount among them.
x : y : z = (1/3) : (2/3) : (3/8) = 8 : 16 : 9
8 + 16 + 9 = 33
8 : 33 = x : 6650
x = $1612.12
16 : 33 = y : 6650
y = $3224.24
9 : 33 = z : 6650
z = $1813.64
the largest amount among is $3224.24

2007-06-06 20:45:59 補充：
上面 1c 及 1d 做錯了

2007-06-06 20:47:09 補充：
3 也錯了