the grammar maybe wrong, but the meaning is the same:
Peter has been driving for x hours at 40km/h and y hours at 60km/h(the distance is 1800km/h).
Then he return to the starting point at the speed of 50km/h, 比之前所需的時間快2hours.find the value of x and y
聯立方程ans
maths f.3
2009-11-08 2:15 am
回答 (1)
2009-11-08 2:23 am
✔ 最佳答案
40x + 60y = 1800....(1)50(x + y - 2) = 1800....(2)
(1) becomes
2x + 3y = 90...(3)
(2) becomes
x + y - 2 = 36
x + y = 38...(4)
(3) - (4)*2 :
y = 90 - 38*2
y = 14
x = 38-14 = 24
收錄日期: 2021-04-21 22:06:23
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091107000051KK01166