請列明步驟
ps:以上的5 over 7係 7分之5 既意思
更新1:
點解2[x + (5x/7 + 5)] = 250會變做12x/7 + 5 = 125? 拆括號之後唔係2x+10x/7+10=250?
文字方程式(英文)
2009-11-10 5:34 am
Two cars A and B 250 km apart are travelling towards each other on the same road.The travelling speed or car B is 5km/h more than 5 over 7 of the speed of car A.They will meet after 2 hours.Find the travelling speed of each.
請列明步驟
ps:以上的5 over 7係 7分之5 既意思
請列明步驟
ps:以上的5 over 7係 7分之5 既意思
回答 (1)
2009-11-10 5:47 am
✔ 最佳答案
Let the speed of car A be x km/hThen the speed of car B = (5x/7 + 5) km/h
In 2 hours' time, total distance travelled = 2[x + (5x/7 + 5)] = 250
12x/7 + 5 = 125
x = 70
Speed of car A = 70km/h
Speed of car B = (5/7)(70) + 5 = 55km/h
2009-11-09 22:53:43 補充：
2[x + 5x/7 + 5] = 250
x + 5x/7 + 5 = 125兩邊除以2
7x/7 + 5x/7 + 5 = 125
12x/7 + 5 = 125...
收錄日期: 2021-04-23 23:20:04
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https://hk.answers.yahoo.com/question/index?qid=20091109000051KK01600