Two cars A and B 250 km aparts are travelling towards each other on the same road.The travelling speed of car B is 5 km/h more than 5/7 of the speed of car A.They will meet after 2 hours.Find the travelling speed of each car.
(Applications of Algebraic Equations)
(寫方程式)
幫我help me!!
萬分感謝!!!
F.1 Mathematics in action Ch3
2009-11-01 4:30 am
回答 (2)
2009-11-01 4:40 am
✔ 最佳答案
Let x be speed of car A.Speed of car B = 5 + 5/7×x
As they will meet after 2hours,
250/2 = x + 5 + 5/7×x
12x/7 = 125 - 5 = 120
x = 70
Car B speed = 5 + 5/7 × x = 5 + 5/7 × 70 = 55
=> Speed of car A is 70km/h
Speed of car B is 55km/h
2009-11-01 8:37 am
Let a km/h be the speed of car A, and the )5a/7+ 5)km/h be the speed of car B.
2( a + 5a/7+5) = 250
a+5a/7+5 =125
12a/7 =120
a = 120*7/12
a = 84
So that the speed of car A is 84km/h, and the speed of car B is 84/7*5+5 = 65km/h.
2( a + 5a/7+5) = 250
a+5a/7+5 =125
12a/7 =120
a = 120*7/12
a = 84
So that the speed of car A is 84km/h, and the speed of car B is 84/7*5+5 = 65km/h.
參考: me
收錄日期: 2021-04-13 16:54:43
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091031000051KK01513