1. A shop sells sandwiches and orange juice. 3 sandwiches and 2 cups of orange juice cost $34, while 2 sandwiches and 3 cups of orange cost $31. How much do 1 sandwich and 1 cup of orange juice together cost?
2. If a+2b/8=b/3=b+2c/4, find a:b:c.
3. A car travels at constant speed. If it travels 600m in 45 seconds,
a. find its speed in km/h
b. how long does it take to travel 20km?
中二math-ratio(3題)
2007-08-18 7:01 pm
回答 (2)
2007-08-18 7:07 pm
✔ 最佳答案
3a600m/1000*45/60
3b
20*(600m/1000*45s/60)
2007-08-18 7:22 pm
1.let sandwishes be x and a cup of orange juice be y
3x+2y=34------------(1)
2x+3y=31------------(2)
(1)-(2)
x-y=3
x=3+y------------(3)
sub(3) into (2)
2(3+y)+3y=31
6+2y+3y=31
5y=25
y=5
sub y=5 into (3)
x-y=3
x-5=3
x=8
so x+y=13
2007-08-18 11:32:13 補充：
3.a.600m/45s=600m/1000=0.6km45s/60/60=0.0125hfind its speed in km/h0.6/0.0125=48km/hb.48/60*20=16mins
3x+2y=34------------(1)
2x+3y=31------------(2)
(1)-(2)
x-y=3
x=3+y------------(3)
sub(3) into (2)
2(3+y)+3y=31
6+2y+3y=31
5y=25
y=5
sub y=5 into (3)
x-y=3
x-5=3
x=8
so x+y=13
2007-08-18 11:32:13 補充：
3.a.600m/45s=600m/1000=0.6km45s/60/60=0.0125hfind its speed in km/h0.6/0.0125=48km/hb.48/60*20=16mins
參考: me
收錄日期: 2021-04-25 21:56:51
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https://hk.answers.yahoo.com/question/index?qid=20070818000051KK01235