數學高手請來

1.36km/h

= 3600m / h

= 3600m / 1h

=3600m / 60 min (1h=60min)

=600m / min

= 600m / 60 s (1min=60s)

=10m / s

so the answer is C

2. 在一幅比例為1:25000的地圖上, 某兩個地點的距離是2cm, 求這兩個地點的真實距離.

地圖上的比例，一般都係mm:mm，因此

1:25000 = 1mm : 25000mm

= 1mm : 2500cm

=1mm : 25m

咁依家係2cm長，即係：

2cm (1mm x 20) : 25m x 20

= 2cm : 500m

=2cm : 0.5 km

so the answer is D

3. 以最簡形式寫出下例各比:
i.40cm:25km = 400mm:25 x 1000 x 100 x 10 km = 400mm:25000000mm = 4:250000

ii.1.7kg:680mg = 1.7x100x1000mg:680mg = 170000mg:680mg = 17000:68 = 250:1

iii.1m^2:1cm^2 = 1m X 1m:1cm x 1cm (因為係平方)

= 100cm x 100cm:1cm X1cm

=10000cm^2:1cm^2

=10000:1

iv.1km/h:1m/s = 1000m/h:1m/s

= 1000m/h:1m x 60m/min (60s = 1 min)

= 1000m/h:60 x 60m/h (60min = 1h)

=1000m/h:3600m/h

=1000/3600

=5:18

4. 某校有學生1500人, 男生與女生之比是4:6. 已知5/6的女生及4/5的男生有配戴眼鏡.
a)配戴眼鏡的男生及女生人數

1500 x 4/10 (男生所佔比重) x 4/5 (有戴眼鏡既男生既比重) + 1500 x 6/10(女生所佔比重) x 5/6 (有戴眼鏡既女生既比重)

= 480 (男生) + 750 (女生)

= 1230人

b)求配戴眼鏡興不配戴眼鏡的學生人數之比

1230 (戴眼鏡的學生) : 1500 - 1230 (不戴眼鏡的學生)

= 1230 : 270

= 123: 27

= 41 : 9




希望幫到你

2007-07-21 12:15:29 補充：
漏左題：若AUD$1=US$0.7717及US$1=HK$7.795, 則a)AUD$1=HK$________AUD$1 = US$0.7717US$0.7717 = HK$7.795 x 0.7717 / 1 = HK$6.0154SO, AUD$1=HK$6.0154b)HK$1=AUD$________FROM a), AUD$1=HK$6.0154AUD$1 / 6.0154 = HK$6.0154 / 6.0154AUD$0.16624 = HK$1So, HK$1 = AUD$0.16624

1.C
36x1000
------------
60x60

2.D
2x25000
--------------
100x1000

3.a 1:62500
3.b 2500:1
3.c 10000:1
4.d 25/54:1


4.a 6.0154015
AUD$1=US$0.7717
AUD$1/0.7717=US$0.7717/0.7717
AUD$1/0.7717=US$1
AUD$1/0.7717=US$1=HK$7.795
AUD$1/0.7717=HK$7.795
AUD$1/0.7717x0.7717=HK$7.795x0.7717

4.b 1/(0.7717x7.795)=?自己計
AUD$1/0.7717=HK$7.795
AUD$1/(0.7717x7.795)=HK$7.795/7.795

5.a 配戴眼鏡的男生人數：
=1500x4/(4+6)x4/5
=480(人)
配戴眼鏡的女生人數：
=1500x6/(4+6)x5/6
=720(人)
5.b 4:1
配戴眼鏡的人數：1200
配戴眼鏡的學生人數：300

(我本人沒有正式學過，可能有錯)

1)C
2)D
其他不懂了，對不起。